Showing papers in "American Journal of Epidemiology in 1994"
TL;DR: It is suggested that the increased incidence of Alzheimer's disease in older women may be due to estrogen deficiency and that estrogen replacement therapy may be useful for preventing or delaying the onset of this dementia.
Abstract: The authors explored the possibility that estrogen loss associated with menopause may contribute to the development of Alzheimer's disease by using a case-control study nested within a prospective cohort study. The Leisure World Cohort includes 8,877 female residents of Leisure World Laguna Hills, a retirement community in southern California, who were first mailed a health survey in 1981. From the 2,529 female cohort members who died between 1981 and 1992, the authors identified 138 with Alzheimer's disease or other dementia diagnoses likely to represent Alzheimer's disease (senile dementia, dementia, or senility) mentioned on the death certificate. Four controls were individually matched by birth date (+/- 1 year) and death date (+1 year) to each case. The risk of Alzheimer's disease and related dementia was less in estrogen users relative to nonusers (odds ratio = 0.69, 95 percent confidence interval 0.46-1.03). The risk decreased significantly with increasing estrogen dose and with increasing duration of estrogen use. Risk was also associated with variables related to endogenous estrogen levels; it increased with increasing age at menarche and (although not statistically significant) decreased with increasing weight. This study suggests that the increased incidence of Alzheimer's disease in older women may be due to estrogen deficiency and that estrogen replacement therapy may be useful for preventing or delaying the onset of this dementia.
840 citations
TL;DR: The hypothesis that antioxidant vitamins protect against coronary heart disease is supported, but it cannot be excluded that foods rich in these micronutrients also contain other constituents that provide the protection.
Abstract: Oxidation of lipoproteins is hypothesized to promote atherosclerosis and, thus, a high intake of antioxidant nutrients may protect against coronary heart disease. The relation between the intakes of dietary carotene, vitamin C, and vitamin E and the subsequent coronary mortality was studied in a cohort of 5,133 Finnish men and women aged 30-69 years and initially free from heart disease. Food consumption was estimated by the dietary history method covering the total habitual diet during the previous year. Altogether, 244 new fatal coronary heart disease cases occurred during a mean follow-up of 14 years beginning in 1966-1972. An inverse association was observed between dietary vitamin E intake and coronary mortality in both men and women with relative risks of 0.68 (p for trend = 0.01) and 0.35 (p for trend < 0.01), respectively, between the highest and lowest tertiles of the intake. Similar associations were observed for the dietary intake of vitamin C and carotenoids among women and for the intake of important food sources of these micronutrients, i.e., of vegetables and fruits, among both men and women. The associations were not attributable to confounding by major nondietary risk factors of coronary heart disease, i.e., age, smoking, serum cholesterol, hypertension, or relative weight. The results support the hypothesis that antioxidant vitamins protect against coronary heart disease, but it cannot be excluded that foods rich in these micronutrients also contain other constituents that provide the protection.
636 citations
TL;DR: In this paper, the long-term effects of physically active and sedentary life-styles were studied by comparing groups of young adults who had remained active or inactive in every three examinations.
Abstract: The tracking of physical activity and its influence on selected coronary heart disease risk factors were studied in a 6-year (original survey in 1980, with follow-ups in 1983 and 1986) study of Finnish adolescents and young adults as part of the Cardiovascular Risk in Young Finns Study. The subjects in this analysis were aged 12, 15, and 18 years at baseline. Physical activity was assessed with a standardized questionnaire, and a sum index was derived from the product of intensity, frequency, and duration of leisure time physical activity. Complete data on physical activity index from each study year were available on 961 participants. Significant tracking of physical activity was observed with 3-year correlations of the index ranging from 0.35 to 0.54 in boys and from 0.33 to 0.39 in girls. Tracking was better in older age groups. Two groups of adolescents (active and sedentary groups) were formed at baseline according to high and low values of the index, respectively. Approximately 57% of those classified as inactive remained inactive after a 6-year follow-up. The corresponding value for active subjects was 44% (p < 0.01, active vs. inactive). The long-term effects of physically active and sedentary life-styles were studied by comparing groups of young adults who had remained active or inactive in every three examinations. Serum insulin and serum triglyceride concentrations were significantly lower in active young men. They had a more beneficial high density lipoprotein to total cholesterol ratio and thinner subscapular skinfolds. Among young women, significant differences were seen in adiposity (subscapular skinfold) and in serum triglyceride concentration. Physical activity was also related to less smoking in both sexes and, among young men, to lower consumption of saturated fatty acids and to higher polyunsaturated to saturated fatty acids ratio of the diet. In regression analyses adjusted for the 6-year change in obesity, smoking status, and diet, the change in physical activity was inversely associated with changes in serum insulin and triglycerides in boys. Independent association with triglycerides disappeared when insulin change was added to the model, suggesting that the effect may partly be mediated through insulin metabolism. The authors conclude that the level of physical activity tracks significantly from adolescence to young adulthood. Physical inactivity shows better tracking than does physical activity, and subjects who are constantly inactive express a less beneficial coronary risk profile compared with those who are constantly active.(ABSTRACT TRUNCATED AT 400 WORDS)
508 citations
TL;DR: The authors compared the ability of the National Death Index and the Equifax Nationwide Death Search to ascertain deaths of participants in the Nurses' Health Study and the specificity of both services was approximately 100 percent.
Abstract: The authors compared the ability of the National Death Index and the Equifax Nationwide Death Search to ascertain deaths of participants in the Nurses' Health Study. Each service was sent information on 197 participants aged 60-68 years in 1989 whose deaths were reported by kin or postal authorities and 1,997 participants of the same age who were known to be alive. Neither service was aware of the authors' information regarding participants' vital status. The sensitivity of the National Death Index was 98 percent and that of Equifax was 79 percent. Sensitivity was similar for women aged 65-68 years; however, for women aged 61-64 years, the sensitivity of the National Death Index was 97.7 percent compared with 60.2 percent for Equifax. The specificity of both services was approximately 100 percent. The contrast between the sources of these databases and the matching algorithms they employ has implications for researchers and for those planning health data systems.
490 citations
487 citations
TL;DR: The Spanish version of the Minnesota Leisure Time Physical Activity Questionnaire is a valid instrument to measure the quantity and quality of physical activity performed in the last year by Spanish men aged 20-60 years.
Abstract: Questionnaires are frequently used for measuring physical activity. The aim of this study was to validate the Spanish version of the Minnesota Leisure Time Physical Activity Questionnaire (MLTPAQ) in Spanish men. Healthy men (n = 187) aged 20-60 years were recruited. The MLTPAQ was administered to assess the quantity (total activity metabolic index) and quality (heavy, moderate, and light) of physical activity performed in the last year, quarter, month, and week. Fitness was assessed with an exercise test. Spearman's correlation coefficients between the total activity metabolic index and exercise test duration, time to maximal theoretical heart rate, and caloric intake were 0.57, 0.46, and 0.40, respectively. The intraclass correlation coefficients between the total activity metabolic indexes in the last year and in the last quarter, month, and week were 0.62, 0.46, and 0.35, respectively. In multiple linear regression, the heavy, moderate, and light activity metabolic index, age, body mass index, and basal heart rate explained 40% of the variability of time to the maximum theoretical heart rate. The Spanish version of the MLTPAQ is a valid instrument to measure the quantity and quality of physical activity performed in the last year (also in periods shorter than 1 year) by Spanish men aged 20-60 years. Only heavy physical activity is related to cardiorespiratory fitness.
467 citations
TL;DR: Results from a prospective cohort study of 41,837 women aged 55-69 years who completed a 127-item food frequency questionnaire in 1986 and were monitored for cancer incidence for 5 years are described.
Abstract: Previous epidemiologic studies have shown an inverse association between vegetable and fruit consumption and colon cancer risk; few of these studies have been prospective or have focused on women. This report describes results from a prospective cohort study of 41,837 women aged 55-69 years who completed a 127-item food frequency questionnaire in 1986 and were monitored for cancer incidence for 5 years via the State Health Registry of Iowa. After specific exclusion criteria were applied, 212 colon cancer cases and 167,447 person-years were available for analysis. Intakes of 15 vegetable and fruit groups and dietary fiber were the major factors of interest. Consumption of garlic was inversely associated with risk, with an age- and energy-adjusted relative risk of 0.68 (95% confidence interval (CI) 0.46-1.02) for the uppermost versus the lowermost consumption levels. Inverse associations were also observed for intakes of all vegetables and dietary fiber; age- and energy-adjusted relative risks for the uppermost versus the lowermost intake quartiles were 0.73 (95% CI 0.47-1.13) and 0.80 (95% CI 0.49-1.31), respectively. Associations for the other vegetable and fruit groups were less remarkable.
466 citations
TL;DR: This commentary reviews and illustrates some of the more recent findings about bias in ecologic estimates, and focuses on problems of ecologic confounder control when individual risks follow a nonlinear model.
Abstract: Many authors have pointed out that relative-risk estimates derived from ecologic data are vulnerable to biases not found in estimates derived from individual-level data. Nevertheless, biases in ecologic studies still are often dealt with in the same manner as biases in other observational studies, and so are not given adequate treatment. This commentary reviews and illustrates some of the more recent findings about bias in ecologic estimates. Special attention is given to problems of ecologic confounder control when individual risks follow a nonlinear model, and to misconceptions about ecologic bias that have appeared in the literature.
451 citations
TL;DR: Self-reported medical history and medication use in a cataract case-control study of 1,380 persons in Boston, Massachusetts, suggests an accurate recall of medical and drug usage history in well-defined chronic conditions.
Abstract: The authors compared self-reported medical history and medication use in a cataract case-control study of 1,380 persons (1985-1989) in Boston, Massachusetts, with information from the participants' physicians. Under- and overreporting varied by condition and type of medication. A self-reported history of hypertension had the highest sensitivity (91%), and diabetes history had the highest specificity (97%). Among different medications investigated, self-reported antihypertensive medication use was the most sensitive (88%), while self-reported use of insulin was the most specific (99%). Differences between patient- and physician-reported frequencies were very small, except for arthritis (15%) and regular aspirin use (21%). Results suggest an accurate recall of medical and drug usage history in well-defined chronic conditions.
449 citations
TL;DR: In this paper, the authors argue that meta-analysis is essential for obtaining reproducible summaries of study results and valuable for discovering patterns among study results, and emphasize the subjective components of these processes and vigorously search for sources of heterogeneity.
Abstract: Meta-analysis is essential for obtaining reproducible summaries of study results and valuable for discovering patterns among study results. A good meta-analysis will highlight and delineate the subjective components of these processes and vigorously search for sources of heterogeneity. Unfortunately, these objective are not always met by common techniques. For example, a scatterplot is an objective summarization if the data are uncensored, but inferred patterns should be regarded as subjective recognitions of the analyst, not objective data properties. Random-effects summaries encourage averaging over important data patterns, divert attention from key sources of heterogeneity, and can amplify distortions produced by publication bias; such summaries should only be used when important heterogeneity remains after a thorough search for the sources of such heterogeneity. Quality scoring adds the analyst's subjective bias to the results, wastes information, and can prevent the recognition of key sources of heterogeneity; it should be completely replaced by meta-regression on quality items (the score components).
442 citations
TL;DR: Overall, the effect of reproductive factors appears to influence cumulative incidence to age 70 years by a maximum of approximately 50% when women with multiple births with an early age at first birth are compared with women with a single birth at a late age.
Abstract: A modification of the model of Pike et al. (Nature 1983;303: 767-70) was applied to 91,523 women in the Nurses' Health Study who did not report prevalent cancer initially and who were followed for 14 years (1,212,855 person-years and 2,341 incident breast cancers). The model took into account current age, age at all births, age at menopause, and age at menarche in predicting the annual and cumulative incidence of breast cancer. The authors found that ages both at first birth and at subsequent births have long-term influence on breast cancer incidence. The incidence density for parous women was greater than for nulliparous women for 20-30 years after the time of the first birth. However, cumulative incidence up to age 70 years was about 20% lower, 10% lower, or 5% higher for parous versus nulliparous women if their first birth was at age 20, 25, or 35 years, respectively. The authors also observed a significantly lower incidence after each additional birth as well as after menopause for women of the same age. Overall, the effect of reproductive factors (other than age at menarche) appears to influence cumulative incidence to age 70 years by a maximum of approximately 50% when women with multiple births with an early age at first birth are compared with women with a single birth at a late age.
TL;DR: The chronic arsenic exposure may induce diabetes mellitus in humans, and residents in villages where the chronic arseniasis was hyperendemic had a twofold increase in age- and sex-adjusted prevalence of Diabetes mellitus compared with residents in Taipei City and the Taiwan area.
Abstract: To examine the association between ingested inorganic arsenic and prevalence of diabetes mellitus, in 1988, the authors studied 891 adults residing in villages in southern Taiwan where arseniasis is hyperendemic. The status of diabetes mellitus was determined by an oral glucose tolerance test and a history of diabetes regularly treated with sulfonylurea or insulin. The cumulative arsenic exposure in parts per million-years was calculated from the detailed history of residential addresses and duration of drinking artesian well water obtained through standardized interviews based on a structured questionnaire and the arsenic concentration in well water. The body mass index was derived from body height and weight measured according to a standard protocol, while the physical activity at work was also obtained by questionnaire interviews. Residents in villages where the chronic arseniasis was hyperendemic had a twofold increase in age- and sex-adjusted prevalence of diabetes mellitus compared with residents in Taipei City and the Taiwan area. There was a dose-response relation between cumulative arsenic exposure and prevalence of diabetes mellitus. The relation remained significant after adjustment for age, sex, body mass index, and activity level at work by a multiple logistic regression analysis giving a multivariate-adjusted odds ratio of 6.61 and 10.05, respectively, for those who had a cumulative arsenic exposure of 0.1-15.0 and greater than 15.0 ppm-year compared with those who were unexposed. These results suggest the chronic arsenic exposure may induce diabetes mellitus in humans.
TL;DR: There were no clear dose-response trends with increasing exposure and no consistency among the three utilities, and no association with magnetic fields was observed for any of the 29 types of cancer studied, including skin melanoma, male breast cancer, and prostate cancer.
Abstract: To determine whether occupational exposure to magnetic fields of 50-60 Hz was associated with cancer among electric utility workers, the authors used a case-control design nested within three cohorts of workers at electric utilities: Electricite de France--Gaz de France, 170,000 men; Ontario Hydro, 31,543 men; and Hydro-Quebec, 21,749 men. During the observation period, 1970-1989, 4,151 new cases of cancer occurred. Each participant's cumulative exposure to magnetic fields was estimated based on measurements of current exposure of 2,066 workers performing tasks similar to those in the cohorts using personal dosimetry. Estimates were also made of past exposure based on knowledge of current loading, work practices, and usage. Workers who had more than the median cumulative exposure to magnetic fields (3.1 microtesla (microT)-years) had a higher risk for acute nonlymphoid leukemia (odds ratio (OR) = 2.41, 95% confidence interval (CI) 1.07-5.44). The same observation holds for acute myeloid leukemia (OR = 3.15, 95% CI 1.20-8.27). There was also an elevated risk for mean exposure above 0.2 microT (acute nonlymphoid leukemia, OR = 2.36, 95% CI 1.00-5.58; acute myeloid leukemia, OR = 2.25, 95% CI 0.79-6.46). However, there were no clear dose-response trends with increasing exposure and no consistency among the three utilities. Men whose cumulative exposure to magnetic fields was above the 90th percentile (15.7 microT-years) had an elevated risk for brain cancer (OR = 1.95, 95% CI 0.76-5.00) that was not statistically significant. No association with magnetic fields was observed for any of the other 29 types of cancer studied, including skin melanoma, male breast cancer, and prostate cancer. Controlling for potential confounding factors did not change the results.
TL;DR: This study provides no evidence that estrogen replacement therapy has an impact on the risk of Alzheimer's disease in women.
Abstract: Preliminary animal and human data suggest that estrogens may be protective against Alzheimer's disease in women. In a population-based case-control study at Group Health Cooperative of Puget Sound, Seattle, Washington, the authors compared the exposure of estrogen replacement therapy of 107 female Alzheimer's disease cases with 120 age- and sex-matched controls by using computerized pharmacy data. The cases were obtained from the Alzheimer's Disease Patient Registry of the University of Washington, Seattle, Washington, which is based on the enumerated health plan population from 1987 to 1992. Newly recognized cases of probable Alzheimer's disease according to standardized diagnostic criteria were ascertained, evaluated, and enrolled in the Registry. The controls were selected from the same defined population by stratified random sampling. When the authors applied logistic regression, ever use of estrogens did not show an association with Alzheimer's disease (adjusted odds ratio = 1.1, 95 percent confidence interval 0.6-1.8). Oral and vaginal estrogens yielded similar results. In conclusion, this study provides no evidence that estrogen replacement therapy has an impact on the risk of Alzheimer's disease in women.
TL;DR: The software for analysis of the Health Habits and History Questionnaire has been revised and is available to researchers and the validity is unchanged from the previous software.
Abstract: The software for analysis of the Health Habits and History Questionnaire (HHHQ) has been revised and is available to researchers. As in earlier versions of the software, questionnaires other than the standard National Cancer Institute versions can be analyzed. Foods can be added or dropped, nutrients can be added or changed, and many other revisions and options are facilitated. Estimates of 33 nutrients and up to 20 user-defined food groups are produced. The validity is unchanged from the previous software. Other features include a data entry key-and-verify system, standardized editing, a computer-assisted interview, and the calculation of health indices including pack-years of smoking and social network index.
TL;DR: The prevalence of subclinical atherosclerosis and cardiovascular disease was evaluated among the 5,201 adults aged > or = 65 years in four communities participating in the Cardiovascular Health Study from June 1989 through May 1990 and the risk factors are similar to those for clinical disease at younger ages, especially among women.
Abstract: The prevalence of subclinical atherosclerosis and cardiovascular disease was evaluated among the 5,201 adults aged > or = 65 years in four communities participating in the Cardiovascular Health Study from June 1989 through May 1990. A combined index based on electrocardiogram and echocardiogram abnormalities, carotid artery wall thickness and stenosis based on carotid ultrasound, decreased ankle-brachial blood pressure, and positive response to a Rose Questionnaire for angina or intermittent claudication defined subclinical disease. The prevalence of subclinical disease was 36% in women and 38.7% in men and increased with age. Among women, low-density lipoprotein cholesterol, systolic blood pressure, blood glucose, and cigarette smoking were positively associated, and high-density lipoprotein cholesterol negatively associated, with subclinical disease. In men, systolic blood pressure, blood glucose, and cigarette smoking were independent risk factors in multiple logistic regression analyses. The risk factors for subclinical disease are, therefore, similar to those for clinical disease at younger ages, especially among women. It is possible that older individuals with subclinical disease are at very high risk of developing clinical disease and that more aggressive interventions to prevent clinical disease should be oriented to individuals with subclinical disease.
TL;DR: Smoking, use of hormones, body mass index, and age at first full-term pregnancy appear to be associated with age at natural menopause in a representative sample of Finnish women.
Abstract: Differences in age at natural menopause by occupation education and place of residence were examined using a cross-sectional population sample of Finnish women aged 45-64 years (n = 1713 response rate 86%). The sample was selected at random from the Finnish Population Register in 1989 (final n = 1505 75%). Kaplan-Meier estimates showed the median age at natural menopause to be 51 years for all women.... The effects of parity and smoking on age at menopause are also considered. The results suggest that sociodemographic variables do affect the age at menopause in this group of women. (EXCERPT)
TL;DR: It was found that childbearing and use of oral contraceptives were associated with significant decreasing trends in risk of ovarian cancer; the respective odds ratios were 0.78 for each full-term pregnancy and 0.92 for each year of use.
Abstract: A case-control study of reproductive factors and cancer of the ovary was conducted during 1989-1992 in metropolitan Toronto and nearby areas of Southern Ontario, Canada. In total, 450 women aged 35-79 years with histologically verified new primary epithelial ovarian cancers were interviewed concerning their reproductive histories. Over the same time period, 564 randomly selected population controls, frequency-matched to the cases according to three 15-year age groups, were also interviewed. Continuous unconditional logistic regression methods were used for analysis. It was found that childbearing and use of oral contraceptives were associated with significant decreasing trends in risk of ovarian cancer; the respective odds ratios were 0.78 for each full-term pregnancy (p < 10(-8)) and 0.92 for each year of use (p < 10(-6)). Hysterectomy was also associated with reduced risk, even after more than 20 years. Among parous women, infertility did not appear to affect risk; for nulliparous women, some evidence of increased risk was present, although fertility problems were reported by only a small fraction of nulliparae. It is suggested that the relatively lower parity of cases as compared with controls may be due to voluntary choices for having fewer children.
TL;DR: It is concluded that a high level of total cholesterol and a low level of high density lipoprotein cholesterol are important risk factors for erectile dysfunction.
Abstract: Although erectile dysfunction is frequently seen in patients with manifestations of arteriosclerotic disease, the independent contribution of serum cholesterol in predicting erectile dysfunction is unclear The aim of this study was to examine the relation between serum cholesterol and erectile dysfunction Medical histories, physical examinations, and blood tests were obtained at Cooper Clinic, Dallas, Texas, from 3,250 men aged 26-83 years (mean, 51 years) without erectile dysfunction at their first visit, who had one more clinic visit, all between 1987 and 1991 These men were followed 6-48 months after the first clinic visit (mean, 22 months) Erectile dysfunction was reported in 71 men (22%) during follow-up Every mmol/liter of increase in total cholesterol was associated with 132 times the risk of erectile dysfunction (95% confidence interval 104-168), while every mmol/liter of increase in high density lipoprotein cholesterol was associated with 038 times the risk (95% confidence interval 018-080) Men with a high density lipoprotein cholesterol measurement over 155 mmol/liter (60 mg/dl) had 030 times the risk (95% confidence interval 009-103) as did men with less than 078 mmol/liter (30 mg/dl) Men with total cholesterol over 621 mmol/liter (240 mg/dl) had 183 times the risk (95% confidence interval 100-337) as did men with less than 465 mmol/liter (180 mg/dl) Those differences remained essentially unchanged after adjustment for other potential confounders The authors conclude that a high level of total cholesterol and a low level of high density lipoprotein cholesterol are important risk factors for erectile dysfunction
TL;DR: Baseline obesity, as measured by an index of relative weight, was found to be significantly associated with the 23-year incidence of osteoarthritis of the hands among subjects disease free at baseline and there was no evidence that development of osteOarthritis subsequently led to increased incidence of obesity.
Abstract: The Tecumseh Community Health Study provides an opportunity to investigate the role of obesity in the etiology of osteoarthritis. This longitudinal study, conducted in Tecumseh, Michigan, began in 1962 with baseline examinations of clinical, biochemical, and radiologic characteristics. A 1985 reexamination of the cohort characterized osteoarthritis status in 1,276 participants, 588 males and 688 females, who were aged 50-74 years at this follow-up. Baseline obesity, as measured by an index of relative weight, was found to be significantly associated with the 23-year incidence of osteoarthritis of the hands among subjects disease free at baseline. Greater baseline relative weight was also associated with greater subsequent severity of osteoarthritis of the hands. The difference between baseline and follow-up weight values was not significantly associated with the incidence of osteoarthritis of the hands. Furthermore, there was no evidence that development of osteoarthritis subsequently led to increased incidence of obesity.
TL;DR: The authors review the strengths and weaknesses of several approaches for dealing with this problem, using data from a school-based smoking cessation trial and a principal conclusion is that the choice of method should depend on whether or not random allocation is used in the assignment of interventions.
Abstract: The aim of many research investigations is to compare the proportion of individuals in each of several groups that have a certain characteristic. The unit of allocation for such investigations is often an intact social unit, as in randomizing families, medical practices, schools, or entire communities, to different intervention groups. Standard statistical methods are not appropriate for these designs, since they do not take into account the dependencies among individuals within the same cluster. The authors review the strengths and weaknesses of several approaches for dealing with this problem, using data from a school-based smoking cessation trial. A principal conclusion is that the choice of method should depend on whether or not random allocation is used in the assignment of interventions.
TL;DR: It is concluded that physical activity may be important in reducing the risk of stroke, particularly among nonsmoking men in older middle age.
Abstract: From 1965 to 1968, the Honolulu Heart Program began following 8,006 men in a prospective study of cardiovascular disease. At the time of study enrollment, an estimate of current 24-hour habitual physical activity was collected from each subject. On the basis of a calculated physical activity index, subjects were classified as being inactive, partially active, or active. This report examines the relation between the levels of physical activity and stroke that occurred among 7,530 of the men over 22 years of follow-up. Risk of stroke was examined separately in younger (45-54 years) middle-aged men and older (55-68 years) middle-aged men. Among the older men, those who were inactive or partially active experienced a three- to fourfold excess incidence of hemorrhagic stroke as compared with active men (p < 0.01). There was a two- to threefold excess of intracerebral hemorrhage in men who were inactive or partially active as compared with those who were active (p < 0.05). An excess of subarachnoid hemorrhage was observed in inactive older men, with only one event occurring in those who were active (p < 0.05). After exclusion of subjects with hypertension, diabetes mellitus, and left ventricular hypertrophy, the relative risk of hemorrhagic stroke for inactive men versus active men was 3.7 (95% confidence interval (CI) 1.3-10.4). In older men who did not smoke cigarettes, the relative risk of thromboembolic stroke among inactive men versus active men was 2.8 (95% CI 1.2-6.7), and when partially active older men were compared with those who were active, the relative risk was 2.4 (95% CI 1.0-5.7). These findings persisted after control for the residual effects of systolic blood pressure and other risk factors for stroke. Benefits of physical activity in reducing the risk of thromboembolic stroke were not observed in men who smoked cigarettes. The authors conclude that physical activity may be important in reducing the risk of stroke, particularly among nonsmoking men in older middle age.
TL;DR: The authors conclude that the effects of exposure to tobacco smoking by the mother during pregnancy and/or environmental tobacco smoke exposure in the first few years of life persist into childhood and may affect the pulmonary function attained throughout the child's life.
Abstract: Recent studies have suggested that prenatal exposure to environmental tobacco smoke may lead to lower lung function in infants. The authors examined the relation of maternal smoking during pregnancy to persistent deficits in the lung function of older children. Subjects were 8,863 nonsmoking white children aged 8-12 years from 22 North American communities. Information on maternal smoking was provided by the child's mother. Pulmonary function testing of the children was conducted at school in 1988-1991. Children whose mothers smoked during pregnancy, whether or not they still smoked in the year prior to the study, had significantly lower lung function than did children whose mothers did not smoke in either period. On average, forced expiratory flow between 65 and 75 percent of forced vital capacity (FEF65-75%), forced expiratory flow between 25 and 75 percent of forced vital capacity (FEF25-75%), and forced expiratory volume in 3/4 of a second (FEV0.75) were 5.7%, 4.9%, and 1.7% lower, respectively, for children whose mothers smoked during pregnancy. After adjusting for maternal smoking during pregnancy, the authors found that current maternal smoking was not associated with significant differences on any lung function measure. These results show a persistent deficient in lung function associated with maternal smoking during pregnancy that is not explained by current maternal smoking alone. The strongest effects were observed with pulmonary function measures of flow in the small airways. The authors conclude that the effects of exposure to tobacco smoking by the mother during pregnancy and/or environmental tobacco smoke exposure in the first few years of life persist into childhood and may affect the pulmonary function attained throughout the child's life.
TL;DR: Examination of smoking by pack-years revealed an apparent dose-response effect on the risk of idiopathic Parkinson's disease, but not on the age of onset, apparently because of its association with cigarette smoking.
Abstract: A 26-year follow-up study of 8,006 men enrolled in the Honolulu Heart Program examined the effect of cigarette smoking on the risk of developing idiopathic Parkinson's disease. Cases were identified through an ongoing search of hospital records and by the review of death certificates and medical records of local neurologists. Men who had smoked cigarettes at any time prior to study enrollment in 1965 had a reduced risk of developing idiopathic Parkinson's disease (relative risk = 0.39). Examination of smoking by pack-years revealed an apparent dose-response effect on the risk of idiopathic Parkinson's disease, but not on the age of onset. Coffee drinking was also associated with reduced risk, apparently because of its association with cigarette smoking. Although the detrimental health effects of cigarette smoking would far outweight any possible protective effect for smoking and Parkinson's disease, the association of smoking with apparent protection may contribute to understanding the underlying pathogenetic mechanisms.
TL;DR: Results were not sensitive to alternative methods for controlling for seasonal patterns and weather, nor to the exclusion of very hot or cold days, and nonparametric smoothing found no evidence of a threshold in the relation.
Abstract: Several studies have reported associations between airborne particles and/or ozone and hospital admissions for respiratory disease. This study examined whether such an association could be seen in Birmingham, Alabama, one of the few cities in the United States with daily monitoring of inhalable particles. Daily counts of hospital admissions were computed by date of admission from Medicare records for pneumonia and chronic obstructive pulmonary disease for the years 1986-1989. Classification was by discharge diagnosis. The daily average of ozone and particulate matter with an aerodiameter of < or = 10 microns (PM10) from all monitoring stations in Birmingham was computed. Approximately six admissions for pneumonia and two for chronic obstructive pulmonary disease were observed each day. In Poisson regression analysis controlling for time trends, seasonal fluctuations, and weather, inhalable particles were a risk factor for admission for pneumonia (for an increase of 100 micrograms/m3 in daily concentration, relative risk (RR) = 1.19, 95% confidence interval (CI) 1.07-1.32) and chronic obstructive pulmonary disease (RR = 1.27, 95% CI 1.08-1.50). The results were not sensitive to alternative methods for controlling for seasonal patterns and weather, nor to the exclusion of very hot or cold days. Ozone was more weakly associated with admissions for pneumonia, with a 2-day lag (RR = 1.14, 95% CI 0.94-1.38), and for chronic obstructive pulmonary disease, with a 1-day lag (RR = 1.17, 95% CI 0.86-1.60). The risks are for an increase in ozone exposure of 50 parts per billion. Tests for nonlinearity in the relation between inhalable particles and admissions were not significant, and nonparametric smoothing found no evidence of a threshold in the relation.
TL;DR: Physical activity and dietary factors such as the intake of fatty acids, fiber, carbohydrates, and alcohol, were independently associated with hyperinsulinemia and insulin resistance and behavioral factors may partly determine the occurrence of non-insulin-dependent diabetes mellitus and coronary heart disease and play a role in the prevention of these disorders.
Abstract: The relation of dietary factors and physical activity to hyperinsulinemia was examined in 389 men aged 70-89 years who participated in the Zutphen Elderly Study in 1990. Information about the usual diet was obtained using a cross-check dietary history, and habitual physical activity was assessed using a validated questionnaire. Known and newly diagnosed diabetic patients were excluded from this study, since serum insulin and C-peptide levels are indicators of insulin resistance and hyperinsulinemia in non-diabetics only. Insulin levels during the oral glucose tolerance test were lowest in men with the highest physical activity. This inverse association was independent of age, body mass index, the ratio of subscapular to triceps skinfold thickness, cigarette smoking, and energy intake (p < 0.001). In addition, insulin levels were inversely associated with the intake of dietary fiber and polyunsaturated fatty acids, which could not be accounted for by variables such as energy intake, body mass index, physical activity, prescribed diets, or the presence of coronary heart disease. In contrast, insulin levels increased with the increasing intake of saturated fatty acids and alcohol. The fasting C-peptide level was independently associated with the intake of total fat, saturated and monounsaturated fatty acids, and alcohol, whereas an inverse relation with the intake of total carbohydrates and dietary fiber was seen. Besides overweight, physical activity and dietary factors such as the intake of fatty acids, fiber, carbohydrates, and alcohol, were independently associated with hyperinsulinemia and insulin resistance. Therefore, these behavioral factors may partly determine the occurrence of non-insulin-dependent diabetes mellitus and coronary heart disease and play a role in the prevention of these disorders.
TL;DR: It is suggested that abdominal obesity in men may increase the frequency and severity of urinary obstructive symptoms and the likelihood that such obese men will undergo a prostatectomy.
Abstract: Abdominal obesity increases the estrogen-to-androgen ratio and may increase sympathetic nervous activity, both hypothesized to influence the development of benign prostatic hyperplasia and the severity of urinary obstructive symptoms. In 1986 and 1987, men aged 40-75 years who were participants in the Health Professionals Follow-up Study and who were without prior diagnosis of cancer or prostatectomy provided data on weight, height, and waist and hip circumferences. The men were followed for incidence of prostatectomy for benign prostatic hyperplasia up to January 1992. In addition, the frequency and severity of symptoms of urinary obstruction were assessed among respondents to a questionnaire in 1992. Among 25,892 men who provided complete information for both surgery and symptoms, 837 men had surgery for benign prostatic hyperplasia, and 2,581 of those without surgery reported frequent urinary symptoms. After adjustment for age, smoking, and body mass index, abdominal obesity was related to prostatectomy (odds ratio (OR) = 2.38, 95% confidence interval (CI) 1.42-3.99, for those with a waist circumference > or = 43 inches (109 cm) relative to those with a waist circumference < 35 inches (89 cm); p trend < 0.0001) and with frequent urinary symptoms among those without prostatectomy (OR = 2.00, 95% CI 1.47-2.72; p < 0.0001). Body mass index, hip circumference, and waist-to-hip ratio were not associated with benign prostatic hyperplasia independently of waist circumference. These results suggest that abdominal obesity in men may increase the frequency and severity of urinary obstructive symptoms and may increase the likelihood that such obese men will undergo a prostatectomy.
TL;DR: The authors present a method for defining the inception of perimenopause based on self-reported data that is based on the ability of responses to questions concerning timing of the last menstrual period, menstrual regularity, and presence of menopausal symptoms to predict menopause 3 years later.
Abstract: The authors present a method for defining the inception of perimenopause that is based on self-reported data. The study sample (n = 1,550) was obtained from a 5-year longitudinal study of 2,569 Massachusetts women aged 45-55 years that began in 1981. The definition was derived from the ability of responses to questions concerning timing of the last menstrual period, menstrual regularity, and presence of menopausal symptoms (hot flashes/sweats) to predict menopause 3 years later. The two items that best defined the inception of perimenopause were 3-11 months of amenorrhea and increased menstrual irregularity for those without amenorrhea. This definition can easily be used in large epidemiologic investigations.