Showing papers in "American Journal of Epidemiology in 1988"

Factors associated with osteoarthritis of the knee in the first national health and nutrition examination survey (hanes i) evidence for an association with overweight, race, and physical demands of work

Abstract: The authors used data from the United States first national Health and Nutrition Examination Survey of 1971-1975 (HANES I) to explore the cross-sectional associations between radiographic osteoarthritis of the knee and a variety of putative risk factors. A total of 5,193 black and white study participants aged 35-74 years, 315 of whom had x-ray-diagnosed osteoarthritis of the knee, were available for analysis. After controlling for confounders, the authors found significant associations of knee osteoarthritis with overweight, race, and occupation, all of which have been suggested by smaller cross-sectional studies. They then focused specifically on those factors. For overweight, they found a strong association between current obesity and osteoarthritis of the knee, with a dose-response effect not previously assessed. This association was also seen for self-reported minimum adult weight, a proxy for long-term obesity, and was present in persons with asymptomatic osteoarthritis of the knee. These findings strongly suggest that obesity is causative. HANES I was the first study in which racial differences in osteoarthritis of the knee could be assessed within the same country. The black women who were studied had an increased risk of disease (odds ratio (OR) = 2.12, 95% confidence interval (CI) = 1.39-3.23) after controlling for age and weight, although the black men did not. Finally, the authors used the US Department of Labor Dictionary of Occupational Titles to obtain characterizations of the physical demands and knee-bending stress associated with occupations and to study the relation between physical demands of jobs and osteoarthritis of the knee. They found for persons aged 55-64 years an association between knee-bending demands and osteoarthritis of the knee (men, OR = 2.45, 95% CI = 1.21-4.97; women, OR = 3.49, 95% CI = 1.22-10.52). Since such occupational physical demands are common, the authors conclude that they may be associated with a substantial proportion of osteoarthritis of the knee.

The use of a self-administered questionnaire to assess diet four years in the past

Abstract: The use of a mailed, self-administered, semiquantitative food frequency questionnaire to describe past dietary intake was evaluated in 1984 among a group of 150 Boston-area women who had completed four one-week diet records three to four years previously. Correlation coefficients comparing calorie-adjusted nutrient intakes computed from the questionnaire with those obtained from a compressed version of the questionnaire completed during diet record keeping ranged from 0.44 for total carbohydrate to 0.62 for vitamin C including supplements. Coefficients comparing calorie-adjusted nutrient intakes measured by questionnaire with those assessed by the diet records completed three to four years previously ranged from 0.28 for iron without supplements to 0.61 for total carbohydrate. An evaluation of the incremental contribution provided by several open-ended sections of the questionnaire to the estimation of nutrient intake suggested that in this population most of these items might be eliminated without material loss of information. These findings demonstrate that useful estimates of nutrient intake several years previously can be obtained by a relatively inexpensive, mailed, self-administered questionnaire.

Case-control study of childhood cancer and exposure to 60-hz magnetic fields

Abstract: Concern with health effects of extremely low frequency magnetic fields has been raised by epidemiologic studies of childhood cancer in relation to proximity to electric power distribution lines. This case-control study was designed to assess the relation between residential exposure to magnetic fields and the development of childhood cancer. Eligible cases consisted of all 356 residents of the five-county 1970 Denver, Colorado Standard Metropolitan Statistical Area aged 0-14 years who were diagnosed with any form of cancer between 1976 and 1983. Controls were selected by random digit dialing to approximate the case distribution by age, sex, and telephone exchange area. Exposure was characterized through in-home electric and magnetic field measurements under low and high power use conditions and wire configuration codes, a surrogate measure of long-term magnetic field levels. Measured magnetic fields under low power use conditions had a modest association with cancer incidence; a cutoff score of 2.0 milligauss resulted in an odds ratio of 1.4 (95% confidence interval (CI) = 0.6-2.9) for total cancers and somewhat larger odds ratios (ORs) for leukemias (OR = 1.9), lymphomas (OR = 2.2), and soft tissue sarcomas (OR = 3.3). Neither magnetic fields (OR = 1.0) nor electric fields (OR = 0.9)more » under high power use conditions were related to total cancers. Wire codes associated with higher magnetic fields were more common among case than control homes. The odds ratio to contrast very high and high to very low, low, and buried wire codes was 1.5 (95% CI = 1.0-2.3) for total cases, with consistency across cancer subgroups except for brain cancer (OR = 2.0) and lymphomas (OR = 0.8). Contrasts of very high to buried wire code homes produced larger, less precise odds ratios of 2.3 for total cases, 2.9 for leukemias, and 3.3 for lymphomas.« less

Physical activity and depressive symptoms: the nhanes i epidemiologic follow-up study

Abstract: The relation between self-reported physical activity and depressive symptoms was analyzed for 1,900 healthy subjects aged 25-77 years in the Epidemiologic Follow-up Study (1982-1984) to the first National Health and Nutrition Examination Survey (NHANES I). Depressive symptomatology as measured by the Center for Epidemiologic Studies Depression Scale (CES-D) was examined by sex and race in relation to recreational physical activity and physical activity apart from recreation, controlling for age, education, income, employment status, and chronic conditions. Little or no recreational physical activity and little or no physical activity apart from recreation were cross-sectionally associated with depressive symptoms in whites and in blacks. After exclusion of those with depressive symptoms at baseline, recreational physical activity was an independent predictor of depressive symptoms an average of eight years later in white women. The adjusted odds of depressive symptoms at follow-up were approximately 2 for women with little or no recreational physical activity compared with women with much or moderate recreational physical activity (95% confidence interval 1.1-3.2). These findings are the first indication from a prospective study of a large community sample that physical inactivity may be a risk factor for depressive symptoms.

Reproducibility and validity of dietary assessment instruments i. a self-administered food use questionnaire with a portion size picture booklet

Abstract: A self-administered food use questionnaire which included 276 food items and mixed dishes and a portion size picture booklet with 122 photographs was developed for a large lung cancer intervention trial among approximately 27,000 Finnish men aged 50-69 years. The reproducibility and validity of this questionnaire were studied from March to October 1984. In the reproducibility study, 121 men aged 55-69 years completed the questionnaire three times, at three-month intervals. The intraclass correlations varied from 0.56 for vitamin A to 0.88 for alcohol, with most falling between 0.60 and 0.70. In the validity study, 190 men of similar age kept food consumption records for 12 two-day periods, distributed evenly over a period of six months, and filled in the questionnaire both before and after this period. Correlations between nutrient intake values from the food records and the food use questionnaires ranged from 0.40 for selenium to 0.80 for alcohol. Among subjects who belonged to the lowest quintile on the basis of the food record measurement, an average of 51 per cent fell into the same quintile and 76 per cent fell into the lowest two quintiles when they were categorized on the basis of the food use questionnaire. Findings were similar for the upper tail of the distribution. These data indicate that the self-administered food use questionnaire is useful for measuring individual or group intakes for a variety of nutrients.

The relation of diet, cigarette smoking, and alcohol consumption to plasma beta-carotene and alpha-tocopherol levels

Abstract: The relation of diet and nutritional supplements, cigarette use, alcohol consumption, and blood lipids to plasma levels of beta-carotene and alpha-tocopherol was studied among 330 men and women aged 18-79 years. Dietary carotene, preformed vitamin A, and vitamin E intake were estimated by a self-administered semiquantitative food frequency questionnaire. The correlation of dietary carotene with plasma beta-carotene was reduced in smokers compared with nonsmokers (r = 0.02 vs. 0.44 among men; r = 0.19 vs. 0.45 among women). Smokers had much lower plasma levels of beta-carotene than did nonsmokers (geometric mean 8.5 vs. 15.3 micrograms/dl for men; 17.3 vs. 26.3 micrograms/dl for women) despite only slightly lower intakes of carotenoids. In multiple regression analyses, men who smoked one pack per day had 72% (95% confidence interval (CI) 58-89) of the plasma beta-carotene levels of nonsmokers after accounting for dietary carotene and other variables; for women, the corresponding percentage was 79% (CI 64-99). In similar models, men drinking 20 g of alcohol per day had 76% (CI 65-88) of the beta-carotene levels of nondrinkers; women had 89% (CI 73-108) of the levels of nondrinkers. An interaction term for carotene intake and smoking was statistically significant in a model combining both sexes. These results suggest that plasma levels of beta-carotene among smokers and, perhaps, heavy consumers of alcohol may be reduced substantially below levels due to differences in diet. The correlation of calorie-adjusted intake of vitamin E with lipid-adjusted plasma levels of vitamin alpha-tocopherol was 0.53 for men (n = 137) and 0.51 for women (n = 193) and did not differ by alcohol consumption and cigarette use; these correlations were largely accounted for by use of vitamin supplements. In linear regression models, vitamin E intake and plasma lipids were significant predictors of plasma alpha-tocopherol levels.

Social connections and mortality from all causes and from cardiovascular disease: prospective evidence from eastern Finland.

Abstract: The association between an a priori measure of social connections and five-year mortality from all causes, cardiovascular diseases (International Classification of Diseases, Eighth Revision (ICD-8) codes 390-458), and ischemic heart disease (ICD-8 codes 410-414) was studied in 13,301 men and women from eastern Finland who were first interviewed in 1972 or 1977. For men, there was a graded association between extent of social connections and mortality. In multivariate models with adjustment for age, smoking, serum cholesterol, mean weighted blood pressure, measures of prevalent illness, and other possible confounders, men who were in the two lowest quintiles of the social connections scale were at increased risk compared with those in the highest quintile (odds ratio (OR)all cause = 1.54, 95% confidence interval (CI) = 1.21-1.95; ORcardiovascular disease = 1.54, 95% CI = 1.11-2.13; ORischemic heart disease = 1.34, 95% CI = 0.94-1.90). No strong or consistent association was found for women. The association for men was modified by levels of blood pressure with the effect of low social connections greater at higher levels of blood pressure. In three separate analyses, there was no evidence for confounding or effect modification due to prevalent illness at baseline.

Conceptual problems in the definition and interpretation of attributable fractions.

Abstract: We have argued that the concept of attributable fraction requires separation into the concepts of excess fraction, etiologic fraction, and incidence-density fraction. These quantities do not necessarily approximate one another, and the etiologic fraction is not generally estimable without strong biologic assumptions. For these reasons, care is needed in deciding which (if any) of the concepts is appropriate for a particular application. It appears that the excess fraction (like incidence proportion) will be most relevant in situations that require only consideration of whether disease occurs by a particular time. In situations that require consideration of when disease occurs, direct measures of effect on incidence time may be as relevant as or more relevant than any attributable fraction. To avoid technical complications, we have not discussed additional problems of causal attribution that can arise when exposure has multiple levels or is sustained over time, and the estimation problems that can arise when considering case-control studies, competing risks, or differential censoring. For more detailed discussions of such problems and proposed solutions, see references 11-20.

Factors associated with age-related macular degeneration. An analysis of data from the first National Health and Nutrition Examination Survey.

Abstract: Data from the first National Health and Nutrition Examination Survey collected between 1971 and 1972 were used to determine what factors are associated with the prevalence of age-related macular degeneration. The study was limited to those who were at least 45 years old at the time of the ophthalmology examination. Stratified analysis, adjusting for age, showed that education, systolic blood pressure, past history of hypertension, cerebrovascular disease, and refractive error were all associated with macular degeneration. With the exception of education, these factors remained statistically significant when simultaneously entered into a logistic regression model. The frequency of consumption of fruits and vegetables rich in vitamins A and C suggested a negative association with the prevalence of macular degeneration after stratified adjustment for age. In a logistic regression analysis, adjusting for demographic and medical factors, the inverse association of vitamin C with age-related macular degeneration was no longer present. The frequency of consumption of fruits and vegetables rich in vitamin A remained negatively correlated with age-related macular degeneration even after adjustment for demographic and medical factors.

A mail survey of physical activity habits as related to measured physical fitness

Abstract: The associations of self-reported measures of physical activity from a mail survey with an objective measure of physical fitness were investigated. Respondents to a health status survey (n = 12,225), conducted in 1982 by the Institute for Aerobics Research in Dallas, TX, formed the population. From this group, males who also had a clinical examination within 60 days of the return of their questionnaire served as subjects. The study subjects (n = 375, mean age = 47.1 years) completed a maximal physical fitness assessment using a modified Balke protocol. The questionnaire included a section of inquiries concerning leisure time physical activity participation in which subjects were asked to quantitatively recall exercise participation for varying periods of time. Reported exercise participation values were converted to estimates of energy expenditure and combined into overall indices of physical activity participation. Multiple regression analyses were used to determine the individual contributions of the physical activity indices in predicting maximal treadmill performance (physical fitness). Significant predictors of physical fitness were age (beta = -0.34), an index of running, walking, and jogging participation (beta = 0.31), and the response to a question on frequency of sweating (beta = 0.35). The multiple correlation coefficient for these variables in predicting physical fitness was 0.65. These results indicate that exercise behavior can be accurately estimated in large populations by using simple questions in a mail survey.

Effects of acculturation and socioeconomic status on obesity and diabetes in mexican americans the san antonio heart study

Abstract: The authors hypothesized that increased socioeconomic status and acculturation of Mexican Americans to mainstream US society would be accompanied by a progressive lessening of obesity and non-insulin-dependent diabetes mellitus. This hypothesis was tested in 1979-1982 in the San Antonio Heart Study, a population-based study of 1,288 Mexican Americans and 929 non-Hispanic whites, aged 25-64 years, randomly selected from three San Antonio neighborhoods: a low-income barrio, a middle-income transitional neighborhood, and a high-income suburb. Socioeconomic status was assessed by the Duncan Socioeconomic Index, a global measure of socioeconomic status based on occupational prestige. Acculturation was assessed by three scales which measure functional integration with mainstream society, value placed on preserving Mexican cultural origin, and attitude toward traditional family structure and sex-role organization. In Mexican-American men, increased acculturation was accompanied by a statistically significant, linear decline in both obesity and diabetes, while socioeconomic status had no significant effect on either outcome. In Mexican-American women, on the other hand, increased acculturation and increased socioeconomic status were accompanied by statistically significant, linear declines in both outcomes. However, the effects of acculturation on obesity and diabetes prevalence in women were stronger than the effects of socioeconomic status. In women, obesity also appeared to be a more important mediator of the relation between socioeconomic status and diabetes than of the relation between acculturation and diabetes. The results of this study suggest that culturally mediated factors exert a more pervasive influence on obesity and diabetes in Mexican Americans than do socioeconomically mediated factors. The influence of socioeconomic status in women, however, cannot be ignored, particularly with regard to obesity.

Mortality among diabetics in a national sample

Abstract: The authors compare the mortality experience of a national sample of diabetic men and women with their nondiabetic counterparts. The study population consists of respondents from the First National Health and Nutrition Examination Survey (NHANES I), conducted in 1971-1975, who were traced in 1982-1984 through the NHANES I Epidemiologic Follow-up Study. Over the nine-year follow-up period, the age-adjusted death rates for diabetic men and women were twice the rates for nondiabetics. About 75% of the excess mortality among diabetic men and 57% among diabetic women was attributable to cardiovascular disease deaths. After adjustment for age, systolic blood pressure, serum cholesterol, body mass index, and smoking, the relative risk of death was 2.3 for diabetic men and 2.0 for diabetic women. The relative risk for diabetics was highest for ischemic heart disease mortality (2.8 for men and 2.5 for women) and lowest for noncardiovascular disease deaths (1.4 for men and 1.1 for women). When subjects who reported having had a heart attack prior to the baseline examination were excluded, the relative risks for ischemic heart disease mortality among diabetics remained substantial (2.4 for men and 2.6 for women). There was little evidence that the relative risk of death for diabetics compared with nondiabetics differed by age or sex, although 95% confidence intervals around these estimates were wide.

A prospective study of the development of breast cancer in 16,692 women with benign breast disease

Abstract: The authors studied the relation between benign breast disease and subsequent breast cancer in 16,692 women with biopsy-diagnosed benign breast disease who had participated in the Breast Cancer Detection Demonstration Project throughout the United States. Women were classified into one of five benign breast disease categories: atypical hyperplasia, proliferative disease without atypia, nonproliferative disease, fibroadenoma, and other benign breast disease. A total of 485 incident cases of breast cancer were identified in the women from August 1973 to February 1986 after a median follow-up period of 8.3 years from the diagnosis of benign breast disease. Age-adjusted incidence rates were calculated for benign breast disease types stratified by family history and calcification status. Relative risk (RR) estimates of breast cancer for women in the five benign breast disease categories, compared with the screened women who did not develop recognizable breast disease (normal subjects), were computed using the proportional hazards model. Results indicated that risk was associated with the degree of epithelial atypia. Over all age groups, women with nonproliferative disease, proliferative disease without atypia, and atypical hyperplasia displayed progressively increasing risks of 1.5, 1.9, and 3.0, respectively, compared with normal subjects, with 95% confidence intervals (CI) exceeding unity. Particularly high risk was seen among women under age 46 years with atypical hyperplasia (RR = 5.7, 95% CI 3.0-10.6). Women with fibroadenoma as the only indication of their benign breast disease had a relative risk of 1.7, with a lower 95% confidence limit of 1.0. No increased risk was seen for women with other benign breast disease. Positive family history (RR = 1.8) and calcification (RR = 1.2) significantly increased a woman's risk proportionately over the risk associated with each benign breast disease subtype. The authors conclude that the risk of developing breast cancer varies by category of benign breast disease and is directly related to the degree of epithelial atypia.

The effects of maternal smoking on fetal and infant mortality

Abstract: Although maternal cigarette smoking has been shown to reduce the birth weight of an infant, previous findings on the relation between smoking and fetal and infant mortality have been inconsistent. This study used the largest data base ever available (360,000 birth, 2,500 fetal death, and 3,800 infant death certificates for Missouri residents during 1979-1983) to assess the impact of smoking on fetal and infant mortality. Multiple logistic regression was used to estimate the joint effects of maternal smoking, age, parity, education, marital status, and race on total mortality (infant plus fetal deaths). Compared with nonsmoking women having their first birth, women who smoked less than one pack of cigarettes per day had a 25% greater risk of mortality, and those who smoked one or more packs per day had a 56% greater risk. Among women having their second or higher birth, smokers experienced 30% greater mortality than nonsmokers, but there was no difference by amount smoked. The prevalence of smoking in this population was 30%. It was estimated that if all pregnant women stopped smoking, the number of fetal and infant deaths would be reduced by approximately 10%. The higher rate of mortality among blacks compared with whites could not be attributed to differences in smoking or the other four maternal characteristics studied. In fact, the black-white difference was greater among low-risk women (e.g., married multiparas aged 20 and over with high education) than among high-risk women (e.g., unmarried teenagers with low education).

Relation of cardiovascular fitness and physical activity to cardiovascular disease risk factors in children and adults

Abstract: The associations of physical activity and cardiovascular fitness with cardiovascular disease risk factors were studied in 88 male adults, 180 female adults, 148 male children, and 142 female children. Subjects were families recruited from elementary schools in San Diego, California. Fitness (VO2 max) was measured by a submaximal cycle ergometer test. Physical activity was assessed by seven-day recall interview, yielding caloric expenditure, and by a simple self-rating of activity level. Risk factors included blood pressure, high density lipoprotein (HDL) cholesterol, the ratio of high density lipoproteins to low density lipoproteins (LDL), and body mass index. For all subgroups, fitness was strongly and significantly correlated with virtually all risk factors. After adjustment for body mass index, most fitness-risk factor associations were no longer significant. Seven-day caloric expenditure was significantly correlated with HDL/LDL only in female adults and children. The activity rating was significantly correlated with body mass index in all subgroups and with HDL/LDL in female adults and male adults. The simple activity rating tended to be correlated with fitness. The pattern of association was similar for adults and children.

Interval estimates for correlation coefficients corrected for within-person variation: implications for study design and hypothesis testing

Abstract: It is well known that random measurement error can attenuate the correlation coefficient between two variables. One possible solution to this problem is to estimate the correlation coefficient based on an average of a large number of replicates for each individual. As an alternative, several authors have proposed an unattenuated (or corrected) correlation coefficient which is an estimate of the true correlation between two variables after removing the effect of random measurement error. In this paper, the authors obtain an estimate of the standard error for the corrected correlation coefficient and an associated 100% x (1-alpha) confidence interval. The standard error takes into account the variability of the observed correlation coefficient as well as the estimated intraclass correlation coefficient between replicates for one or both variables. The standard error is useful in hypothesis testing for comparisons of correlation coefficients based on data with different degrees of random error. In addition, the standard error can be used to evaluate the relative efficiency of different study designs. Specifically, an investigator often has the option of obtaining either a few replicates on a large number of individuals, or many replicates on a small number of individuals. If one establishes the criterion of minimizing the standard error of the corrected coefficient while fixing the total number of measurements obtained, in almost all instances it is optimal to obtain no more than five replicates per individual. If the intraclass correlation is greater than or equal to 0.5, it is usually optimal to obtain no more than two replicates per individual.

Life-style risk factors for pancreatic cancer in louisiana: a case-control study

Abstract: A hospital-based, incident case-control study of pancreatic cancer was conducted between 1979 and 1983 in parallel with similarly designed studies of lung and stomach cancers in high-risk areas of Louisiana. To evaluate life-style practices, including diet, the authors pooled controls from the three studies, and then excluded subjects with diet-altering chronic diseases. When the 363 cases were compared with the 1,234 identified controls, significantly elevated risks were found among persons with Cajun ancestry, especially in rural areas. Among current smokers, a significant twofold risk was associated with moderate (16-25 cigarettes per day) and heavy (greater than or equal to 26 cigarettes per day) consumption, while ex-smokers showed no consistent pattern of risk. After adjustment for potential confounding by smoking, diet, and demographic factors, the risk of pancreatic cancer was unrelated to use of alcoholic beverages or coffee. Pork products and rice were conspicuous as dietary risk factors, each showing a positive dose-response effect, whereas fruit consumption exerted a protective influence.

The assessment of historical physical activity and its relation to adult bone parameters

Abstract: The aim of the present research was to determine the association between historical physical activity and baseline bone measurements in a group of 223 postmenopausal women participating in a clinical trial in Pittsburgh, Pennsylvania, from 1981 to 1986 by evaluating the effect of moderate physical activity on bone loss. Historical physical activity was assessed by a survey which divided the life span into four time periods (14-21, 22-34, 35-50, and 50+ years) and inquired about participation in leisure time physical activities for each period. From the responses, kilocalories of energy expenditure were calculated. Cortical bone density and area were measured in the radius with a computerized tomography scanner. The historical physical activity survey was administered a second time two to three months after the initial test to a 10% random sample of the women in order to determine the test-retest reliability of the instrument. Since the measurements of historical physical activity proved to be reliable, estimates of kilocalories determined for the entire population of women were correlated with bone area and density. A significant relation was found to exist between historical physical activity and dimensions of adult bone, particularly bone area. This association remained significant after adjustment for potential confounding variables and seemed to be strongest in the earlier age periods. To the authors' knowledge, this is the first report of a significant association between historical physical activity and bone.

Diet and prostatic cancer: a case-control study in Hawaii

Abstract: A total of 452 cases of prostatic cancer identified through the population-based Hawaii Tumor Registry during the period 1977-1983 and 899 age-matched population controls were interviewed on the island of Oahu from 1981 to 1983. All interviews of the subjects, who comprised five different ethnic groups, were conducted in the home by use of a quantitative dietary history method. Usual weekly intake of fat, zinc, and vitamins A and C, including supplements, was determined for each subject. Among men 70 years or older, but not among younger men, and mean weekly consumption of saturated fat, carotenes, and zinc, adjusted for age and ethnicity, was greater for cases than for controls. In a multiple logistic regression analysis, the odds ratio for the highest quartile of fat intake among the older men was 1.7 (95% confidence interval (CI) 1.0-2.8). The corresponding odds ratios were 1.6 (95% CI 1.0-2.5) for carotenes, 1.4 (95% CI 0.9-2.3) for total vitamin C, and 1.7 (95% CI 1.1-2.7) for total zinc. There were significant linear trends in the odds ratios for saturated fat and zinc, but no synergistic interactions among the nutrients. The findings suggest that several different components of the diet may contribute independently to the risk of prostatic cancer in elderly men.

Acquisition of clostridium difficile from the hospital environment

Abstract: An outbreak of antibiotic-associated colitis that occurred on a ward of a Michigan hospital during February-April, 1984, was studied by bacteriophage-bacteriocin typing. Stools from the seven involved patients yielded Clostridium difficile isolates of types B1537 or Cld7;B1537. C. difficile was recovered from 31.4% of environmental cultures obtained on the ward, and the majority of isolates were types B1537 or Cld7;B1537. When the ward was disinfected with unbuffered hypochlorite (500 parts per million (ppm) available chlorine), surface contamination decreased to 21% of initial levels and the outbreak subsequently ended. Phosphate buffered hypochlorite (1,600 ppm available chlorine, pH 7.6) was even more effective; its use resulted in a 98% reduction in surface contamination. These findings suggest that environmental contamination with C. difficile is important in the epidemiology of antibiotic-associated colitis, and that hypochlorite is effective in eliminating C. difficile from the hospital environment.

Diabetes mellitus: an independent risk factor for stroke?

Abstract: Raised blood pressure is the strongest single risk factor for stroke in the general population. Diabetics are at increased risk of both hypertension and stroke. It is not clear if diabetes mellitus confers an excess risk of stroke that is independent of blood pressure. The authors examined the relation of diabetic status (personal history of diabetes and/or fasting plasma glucose greater than 7.8 mmol per liter) to stroke risk in a population-based cohort of 3,778 adults aged 50-79 years in Rancho Bernardo, California who were followed from 1972 for an average of 12 years. There were 232 stroke cases, 139 of which were ascertained from death certificates. Diabetics had higher mean systolic blood pressures, significantly so in females, and diabetics of both sexes were significantly more obese. Diabetics had greater univariate age-adjusted stroke mortality and morbidity rates than nondiabetics. The increased stroke rates were still apparent in diabetics after stratifying for systolic blood pressure. In multivariate analyses, the relative risks (RRs) for stroke mortality and morbidity associated with diabetes were not significantly changed in men (RR = 1.8) and women (RR = 2.2), after adjusting for the effect of risk factors including age, systolic blood pressure, cholesterol level, obesity, and smoking habits, and excluding persons with personal history of heart attack, heart failure, or stroke. These findings support the hypothesis that diabetes may confer excess risk of stroke independent of blood pressure.

Correlates of cognitive function in an elderly community population

Abstract: In 1982 and 1983, brief, structured performance tests of selected areas of cognitive function were administered to 3,682 (82.1 per cent) of the residents aged 65 years and older of the geographically defined community of East Boston, Massachusetts, a center of the Established Populations for Epidemiologic Studies of the Elderly program. There was a strong inverse relation between age and performance on all four cognitive tests in analyses adjusted for sex only as well as in those adjusted for the effects of other variables. Similarly, fewer years of formal education, increasing level of disability on the modified Katz Activities of Daily Living Scale, and less prestigious occupations, as measured by the modified Duncan Socioeconomic Index, were each independently related to lower performance on all four tests.

Reproducibility and validity of dietary assessment instruments ii. a qualitative food frequency questionnaire

Abstract: The reproducibility and validity of a food frequency questionnaire designed to measure intakes of total fat, saturated and polyunsaturated fats, vitamins A, C, and E, selenium, and dietary fiber were tested from March to October 1984 among 297 Finnish men aged 55-69 years. The questionnaire asked about consumption of 44 food items. In the reproducibility study, 107 subjects filled in the questionnaire three times, at three-month intervals. Intraclass correlations varied from 0.52 for vitamin A to 0.85 for polyunsaturated fat. In the validity study, 190 subjects kept food consumption records for 12 two-day periods distributed evenly over a period of six months and filled in the questionnaire both before and after this period. Correlations between the nutrient intake values from the food records and those from the food frequency questionnaires ranged from 0.33 for selenium to 0.68 for polyunsaturated fat. On the average, 40-45% of the subjects in the lowest and highest quintiles based on food records were in the same respective quintiles when assessed by the food frequency questionnaire, and 70-75% were in the two lowest and two highest questionnaire quintiles, respectively. The food frequency questionnaire and a quantitative food use questionnaire tested in the same study were compared. Use of these two instruments in large-scale epidemiologic studies is discussed.

Body size at different periods of life and breast cancer risk

Abstract: The inconclusive findings of past analytic epidemiologic studies on diet and breast cancer may have resulted from the inability of these studies to assess early dietary exposures. The role of macronutrient intake during early life can be indirectly studied, however, by examining past and present body size. The authors identified by computer linkage a population-based historical cohort of 38,084 women born between 1918 and 1943, on whom information about weight and height had been recorded in Hawaii in both 1942-1943 and 1972. Linkage of this cohort to the Hawaii Tumor Registry resulted in the identification of 607 incident cases of breast cancer for 1972-1983. An average of 4.4 cancer-free controls were matched to each case on year and month of birth and race of the parents. A matched case-control analysis, conducted in each five-year birth cohort, revealed a negative association of adolescent body mass to premenopausal breast cancer. This negative association was statistically significant in girls aged 10-14 years in 1942 (p for trend, 0.004), was present in all ethnic groups, and was strongest among overweight young women who remained overweight in adulthood. Early-age weight, height, and body surface area were not associated with either pre- or postmenopausal breast cancer. Adult weight and gain in body mass since 1942 were positively associated with postmenopausal breast cancer risk. Adjustment for age at first birth, parity and socioeconomic indicators for 1942 and 1972 did not modify the results. This study provides evidence for a protective role of adolescent obesity against premenopausal breast cancer, and for an enhancing role of a positive energy balance during adult life on postmenopausal breast cancer.

Serum vitamin e and risk of cancer among finnish men during a 10-year follow-up

Abstract: The association between serum alpha-tocopherol levels and the subsequent incidence of cancer was investigated in a longitudinal study of 21,172 men initially aged 15-99 years in six geographic areas in Finland. The baseline examination was conducted in 1968-1972, and during the follow-up of 6-10 years, 453 cancers were diagnosed. The serum alpha-tocopherol levels were measured from stored serum samples from these men and from 841 male controls, matched for municipality and age, who did not develop cancer during the follow-up. The mean levels of serum alpha-tocopherol among the cancer cases and controls were 8.02 and 8.28 mg/liter, respectively. A high serum alpha-tocopherol level was associated with a reduced risk of cancer. The relative risk of cancer in persons in the two highest (threshold 8.70 mg/liter) quintiles of serum alpha-tocopherol was 0.64 (95 per cent confidence interval = 0.49-0.85) in comparison with those in the three lowest quintiles. The association was strongest for the combined group of cancers unrelated to smoking and varied between subgroups of the study population as well as between different cancers. The association persisted when adjusted for serum cholesterol, serum vitamin A, serum selenium, and various confounding factors. It also persisted when subjects with possible signs of cancer at the time when the blood samples were drawn or with cancers diagnosed during the first two years of follow-up were excluded. These findings agree with the hypothesis that high vitamin E intake protects against cancer.

Dietary epidemiology of cancer of the colon in western new york

Abstract: The authors interviewed 428 pathologically confirmed cases of colon cancer and controls matched on age, sex, race, and neighborhood in the New York counties containing the cities of Buffalo, Niagara Falls, and Rochester. Risk of colon cancer in both males and females, studied separately, appeared to increase with the amount of total fats and total calories ingested. In addition, we found the risk to increase with increases in the Quetelet index of relative weight (weight (kg)/height (m)2). Dietary fiber was only equivocally associated with risk. Fats and Quetelet index were associated with increased risk in a regression analysis adjusting each factor for the other, as well as for fiber, age, and socioeconomic status. The same was true for calories and Quetelet index. Future efforts to clarify a possible protective role for fiber and to disentangle the effects of fats and calories need to be undertaken. The fact that calories ingested and obesity are each associated with increased risk suggests the importance of studying calorie expenditure.

Exercise and psychologic well-being in the community.

Abstract: In a representative sample of 401 adults in Illinois in 1984, the authors found that increased participation in exercise, sports, and physical activities is associated with improved psychologic well-being. Part of this association is through improved subjective physical health. The authors controlled for potentially confounding factors, including sociodemographic characteristics, instrumentalism, and overweight. They concluded that exercise is associated with decreased symptoms of depression (feelings that life is not worthwhile, low spirits, etc.), anxiety (restlessness, tension, etc.), and malaise (rundown feeling, trouble sleeping, etc.) in the general population, most of which is not severely depressed, and in which many persons are engaged in moderate, nonaerobic exercise.

Can familial aggregation of disease be explained by familial aggregation of environmental risk factors

Abstract: Although familial aggregation has been shown for many if not all diseases, it is often difficult to determine whether such aggregation is due to shared genes or shared environmental factors. The authors examine the effect of familial aggregation of environmental risk factors on familial aggregation of disease when there is no genetic susceptibility. An environmental risk factor with a relative risk (R) for disease and population exposure frequency (f) is assumed to be clustered among siblings with varying degrees of sibling correlation in exposure (c). The impact of varying R, f, and c is examined on two common measures of familial aggregation: the relative risk of disease for siblings of cases compared with siblings of controls, and the sibling recurrence risk. It can be shown that both measures increase with increasing R and c, but decrease at high levels of f. However, even in the face of complete correlation in exposure among siblings (c = 1), environmental risk factors that have values of R less than 10 lead to modest sibling relative risks (ranging from 1 to 2) and low recurrence risks. Similar findings are obtained when familial aggregation of two additive environmental factors is considered. Because many diseases show higher sibling relative risks and recurrence risks, this analysis suggests that simple familial clustering of environmental factors is unlikely to account entirely for familial aggregation of disease, and that genetic factors ought to play an important role in causing familial aggregation.

Alcohol consumption and hip fractures: the framingham study

Abstract: Alcoholics often sustain hip and other fractures. However, a detailed examination of the association between alcohol consumption and hip fractures has not been undertaken. Specifically, the effects of moderate alcohol intake, of alcohol consumption in the elderly, and of changes in consumption have not been studied. Using a retrospective cohort design, the authors evaluated this association in the population-based Framingham Heart Study cohort, a group studied over 35 years and queried repeatedly about their alcohol consumption. In 117,224 person-years of observation, 217 hip fractures occurred. Heavy current alcohol consumption (defined as seven or more ounces (207 ml or more) per week) was associated with a modestly increased risk of hip fracture for women (relative risk (RR) = 1.54) and for men (RR = 1.26) after adjustment for age. In a logistic regression analysis controlling for age, sex, weight, and smoking, current alcohol consumption was associated with a significant (p = 0.01) increase in risk of fracture. The relative risks at different ages were not uniform. For those aged less than 65 years, moderate (2-6 ounces (59.14-177.4 ml) per week) and heavy (seven or more ounces (207 ml or more) per week) were associated with a substantial and significant increased risk, but there was only a marginal and nonsignificant increase in risk in those aged 65 years or more. Examination of the effect of changing alcohol consumption over time indicated that among present heavy alcohol users, past light alcohol consumption reduced the risk (p = 0.03) of fracture, whereas in those with present light consumption, past heavy intake had little effect on fracture risk (p = nonsignificant). In conclusion, alcohol consumption, especially if long-term and heavy, increases the risk of hip fracture. Language: en