Showing papers by "Frank E. Speizer published in 1996"

Postmenopausal Estrogen and Progestin Use and the Risk of Cardiovascular Disease

Abstract: Background Estrogen therapy in postmenopausal women has been associated with a decreased risk of heart disease. There is little information, however, about the effect of combined estrogen and progestin therapy on the risk of cardiovascular disease. Methods We examined the relation between cardiovascular disease and postmenopausal hormone therapy during up to 16 years of follow-up in 59,337 women from the Nurses' Health Study, who were 30 to 55 years of age at base line. Information on hormone use was ascertained with biennial questionnaires. From 1976 to 1992, we documented 770 cases of myocardial infarction or death from coronary disease in this group and 572 strokes. Proportional-hazards models were used to calculate relative risks and 95 percent confidence intervals, adjusted for confounding variables. Results We observed a marked decrease in the risk of major coronary heart disease among women who took estrogen with progestin, as compared with the risk among women who did not use hormones (multivariat...

Birth Weight and Adult Hypertension and Obesity in Women

Abstract: Background Low birth weight has been associated with an increased risk of hypertension, and high birth weight has been associated with increased adult body mass index. Published studies on adults have included only a small number of women. Methods and Results We studied 71 100 women in the Nurses' Health Study I (NHS I) who were 30 to 55 years of age in 1976 and 92 940 women in the Nurses' Health Study II (NHS II) who were 25 to 42 years of age in 1989. Information on birth weight, blood pressure, physician-diagnosed hypertension, and other relevant variables was collected by biennial mailed questionnaire. Ninety-five percent of the women were white. Compared with women in the middle category of birth weight (NHS I, 7.1 to 8.5 lb; NHS II, 7.0 to 8.4 lb), the age-adjusted odds ratio of hypertension in NHS I women with birth weights <5.0 lb was 1.39 (95% CI, 1.29 to 1.50); in NHS II, for birth weights <5.5 lb, the age-adjusted odds ratio was 1.43 (95% CI, 1.31 to 1.56). There was no material change in the e...

Cohort studies of fat intake and the risk of breast cancer--a pooled analysis.

Abstract: Background. Experiments in animals, international correlation comparisons, and case-control studies support an association between dietary fat intake and the incidence of breast cancer. Most cohort studies do not corroborate the association, but they have been criticized for involving small numbers of cases, homogeneous fat intake, and measurement errors in estimates of fat intake. Methods. We identified seven prospective studies in four countries that met specific criteria and analyzed the primary data in a standardized manner. Pooled estimates of the relation of fat intake to the risk of breast cancer were calculated, and data from study-specific validation studies were used to adjust the results for measurement error. Results. Information about 4980 cases from studies including 337,819 women was available. When women in the highest quintile of energy-adjusted total fat intake were compared with women in the lowest quintile, the multivariate pooled relative risk of breast cancer was 1.05 (95 percent confidence interval, 0.94 to 1.16). Relative risks for saturated, monounsaturated, and polyunsaturated fat and for cholesterol, considered individually, were also close to unity. There was little overall association between the percentage of energy intake from fat and the risk of breast cancer, even among women whose energy intake from fat was less than 20 percent. Correcting for error in the measurement of nutrient intake did not materially alter these findings. Conclusions. We found no evidence of a positive association between total dietary fat intake and the risk of breast cancer. There was no reduction in risk even among women whose energy intake from tat was less than 20 percent of total energy intake. In the context of the Western lifestyle, lowering the total intake of fat in midlife is unlikely to reduce the risk of breast cancer substantially. Chemicals/CAS: Dietary Fats

Effects of Cigarette Smoking on Lung Function in Adolescent Boys and Girls

Abstract: Background Little is known about the sex-specific effects of cigarette smoking on the level and growth of lung function in adolescence, when 71 percent of people in the United States who smoke tried their first cigarette. Methods We studied the effects of cigarette smoking on the level and rate of growth of pulmonary function in a cohort of 5158 boys and 4902 girls 10 to 18 years of age, examined annually between 1974 and 1989 in six cities in the United States. Results We found a dose–response relation between smoking and lower levels of both the ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) and the forced expiratory flow between 25 and 75 percent of FVC (FEF25–75). Each pack per day of smoking was associated with a 3.2 percent reduction in FEF25–75 for girls (P = 0.01) and a 3.5 percent reduction in FEF25–75 for boys (P = 0.007). Whereas the FVC level was elevated in smokers, the rate of growth of FVC and FEV1 was reduced. Among adolescents of the same sex, smoking ...

A Prospective Study of Cigarette Smoking and Age-Related Macular Degeneration in Women

Abstract: objective. —To evaluate the relationship between cigarette smoking and incidence of age-related macular degeneration (AMD) among women. Design. —Prospective cohort study with 12 years of follow-up (1980 to 1992), in which information on smoking habits was updated every 2 years. Setting. —Eleven states throughout the United States. Participants. —A total of 31 843 registered nurses enrolled in the Nurses' Health Study who were aged 50 to 59 years in 1980 and did not report a diagnosis of cancer or AMD at the beginning of the study. Additional women entered the analytic cohort as they reached 50 years of age. Main Outcome Measure. —Incidence of AMD with visual loss. Results. —During 556 338 person-years of follow-up, 215 women were newly diagnosed as having AMD. After adjusting for other risk factors for AMD, women who currently smoked 25 or more cigarettes per day had a relative risk (RR) of AMD of 2.4 (95% confidence interval [CI], 1.4-4.0) compared with women who never smoked. Past smokers of this amount also had a 2-fold increased risk (RR=2.0; 95% CI, 1.2-3.4) relative to never smokers. Compared with current smokers, little reduction in risk was suggested even after quitting smoking for 15 or more years. Risk of AMD also increased with an increasing number of pack-years smoked (P for trend Conclusions. —Cigarette smoking is an independent and avoidable risk factor for AMD among women. Because AMD is the most common cause of severe visual impairment among the elderly and treatment is not available or is ineffective for most patients, reducing the risk of this disease is another important reason to avoid smoking.

A prospective study of cigarette smoking and age-related macular degeneration in women

Abstract: Objective.-To evaluate the relationship between cigarette smoking and incidence of age-related macular degeneration (AMD) among women. Design.-Prospective cohort study with 12 years of follow-up (1980 to 1992), in which information on smoking habits was updated every 2 years. Setting.-Eleven states throughout the United States. Participants.-A total of 31 843 registered nurses enrolled in the Nurses' Health Study who were aged 50 to 59 years in 1980 and did not report a diagnosis of cancer or AMD at the beginning of the study. Additional women entered the analytic cohort as they reached 50 years of age. Main Outcome Measure.-Incidence of AMD with visual loss. Results.-During 556338 person-years of follow-up, 215 women were newly diagnosed as having AMD. After adjusting for other risk factors for AMD, women who currently smoked 25 or more cigarettes per day had a relative risk (RR) of AMD of 2.4 (95% confidence interval [Cl], 1.4-4.0) compared with women who never smoked. Past smokers of this amount also had a 2-fold increased risk (RR=2.0 ; 95% Cl, 1.2-3.4) relative to never smokers. Compared with current smokers, little reduction in risk was suggested even after quitting smoking for 15 or more years. Risk of AMD also increased with an increasing number of pack-years smoked (P for trend <.001) ; among women who smoked for 65 or more pack-years, the risk was 2.4 times the risk of never smokers (95% Cl, 1.5-3.8). Analyses of dry and exudative types of AMD and other altemative definitions of AMD revealed similar results. Conclusions.-Cigarette smoking is an independent and avoidable risk factor for AMD among women. Because AMD is the most common cause of severe visual impairment among the elderly and treatment is not available or is ineffective for most patients, reducing the risk of this disease is another important reason to avoid smoking.

Health effects of acid aerosols on North American children: respiratory symptoms.

Abstract: We examined the respiratory health effects of exposure to acidic air pollution among 13,369 white children 8 to 12 years old from 24 communities in the United States and Canada between 1988 and 199...

A Prospective Study of Cigarette Smoking and the Risk of Pancreatic Cancer

Abstract: Objectives: To prospectively examine the excess incidence of pancreatic cancer among cigarette smokers and to examine the influence of smoking cessation on the risk of pancreatic cancer. Methods: We obtained data on cigarette smoking and other risk factors for pancreatic cancer from 118 339 women aged 30 to 55 years and 49 428 men aged 40 to 75 years who were without diagnosed cancer. During the 2116 229 persons-years of follow-up, pancreatic cancer was diagnosed in 186 participants. Results: The multivariate relative risk of pancreatic cancer for current smokers was 2.5 (95% confidence interval, 1.7-3.6). A significant, positive trend in risk with increasing pack-years of smoking was observed ( P for trend=.004), although this association was confined to cigarette consumption within the past 15 years. Compared with participants who continued to smoke, former smokers had a 48% reduction in pancreatic cancer risk within 2 years of quitting. Ultimately, the relative risk of pancreatic cancer among former smokers approached that for never smokers after less than 10 years of smoking cessation. Overall, the proportion of pancreatic cancers attributable to cigarette smoking was 25%. Conclusions: Cigarette smoking is associated with an increased risk of pancreatic cancer. The rapid reduction in risk associated with quitting suggests that smoking cessation could eliminate 25% of the 27 000 deaths from pancreatic cancer occurring annually in the United States. Arch Intern Med. 1996;156:2255-2260

Health effects of acid aerosols on North American children: pulmonary function.

Abstract: We examined the health effects of exposure to acidic air pollution among children living in 24 communities in the United States and Canada. Parents of children between the ages of 8 and 12 complete...

Calcium, Vitamin D, and the Occurrence of Colorectal Cancer Among Women

Abstract: Background: Despite evidence from animal studies for a protective effect of higher calcium and possibly vitamin D intake against colorectal cancer, epidemiologic studies have been inconclusive. Purpose: We investigated the associations between the intake of calcium and vitamin D and the occurrence of colorectal cancer. Methods: In a prospective study, 89 448 female registered nurses who were free of cancer responded to a mailed, semiquantitative food-frequency questionnaire in 1980; dietary information was updated in 1984 and 1986. Through 1992, 501 incident cases of colorectal cancer (396 colon and 105 rectal cancers) were documented. As measures of exposure, we used nutrient intake in 1980 and also two measures of long-term intake on the basis of the three questionnaires: the average of intakes from the three questionnaires and consistent intakes, which were defined as high if women were in the upper tertile on all questionnaires and low if they were in the lower tertile on all questionnaires. To further characterize long-term intake, we conducted analyses excluding women who reported a change in their consumption of milk (primary source of calcium and vitamin D) in the 10 years prior to 1980. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using the lowest quintile of intake as a reference. The Mantel extension test was used to evaluate linear trends across the categories of nutrient intake. In multivariate analyses, the trends were tested with use of the medians of the intake as a continuous variable in the logistic model. The P values for the trends were two-sided. Results: On the basis of the data from the 1980 questionnaire alone, the multivariate RR for colorectal cancer for women in the upper versus the lower quintile were 0.80 (95% CI = 0.60-1.07) for dietary calcium, 0.84 (95% CI = 0.63-1.13) for dietary vitamin D (from foods only), and 0.88 (95% CI = 0.66-1.16) for total vitamin D (from foods and supplements). After the exclusion of women who reported a change in their milk intake, the RRs for colorectal cancer for the highest versus the lowest categories of average intake were 0.74 (95% CI = 0.36-1.50) for dietary calcium, 0.72 (95% CI = 0.34-1.54) for dietary vitamin D, and 0.42 (95% CI = 0.19-0.91) for total vitamin D. The corresponding RRs for the consistency analyses were 0.70 (95% CI = 0.35-1.39) for dietary calcium, 0.59 (95% CI = 0.301.16) for dietary vitamin D, and 0.33 (95% CI = 0.16-0.70) for total vitamin D. Conclusions: These findings do not support a substantial inverse association between calcium intake and risk of colorectal cancer, but an inverse association between intake of total vitamin D and risk of colorectal cancer was suggested. Implications: Available evidence does not warrant an increase in calcium intake to prevent colon cancer, but longer-term studies of both calcium and especially vitamin D in relation to colorectal cancer risk are needed. [J Natl Cancer Inst 1996;88:1375-82]

Environmental tobacco smoke, wheezing, and asthma in children in 24 communities.

Abstract: The association of exposure to environmental tobacco smoke (ETS) at home with asthma and several measures of wheeze was examined among 11,534 children aged 8 to 11 yr in 24 communities in the United States and Canada in 1988 through 1990. Information on the child's respiratory symptoms in the past year and history of exposure to ETS was provided by the child's mother on a questionnaire. After adjusting for potential confounders, children currently exposed to ETS were at greater risk of wheezing with colds (odds ratio [OR] = 1.7; 95% confidence interval [95% CI], 1.4 to 1.9), going to a hospital emergency room for wheeze (OR = 1.6; 95% CI, 1.2 to 2.2), and having persistent wheeze (OR = 1.4; 95% CI, 1.1 to 1.8). The relative odds of these symptoms increased with exposure level, and there was no evidence of a difference in the association with smoking by mother, father, or other adults. In contrast to wheeze symptoms, active doctor-diagnosed asthma and asthma medication use were not significantly associated...

Risk factors for breast cancer according to family history of breast cancer

Abstract: Background : Family history of breast cancer is an established risk factor for this disease and is used to identify women at higher risk, although the impact of risk factors for breast cancer among women with a family history is not well defined. Purpose : Using a modified extended log-incidence Pike model, we prospectively examined the impact of risk factors for breast cancer among women with and without a family history of the disease. Methods : Data analyzed were obtained prospectively from the Nurses' Health Study. Two thousand two hundred forty-nine incident cases of invasive breast cancer were identified in a cohort of 89 132 women aged 30-55 years in 1976 followed biennially through 1990 (1.1 million person-years of follow-up). With the use of proportional hazards models, we evaluated the association between risk factors for breast cancer and risk among women with and those without a family history of the disease. We then fit a modified extended log-incidence Pike model to these data. Results : Among women with a family history of breast cancer, reproductive risk factors had associations that were different from those observed among women without a family history of the disease. In particular, we observed little protection from later age at menarche, no protection from multiple births when compared with nulliparity, nor from early, as compared with later, age at first birth. Fitting these data to a model of breast cancer incidence on the basis of reproductive risk factors, we observed an adverse effect of first pregnancy on risk of breast cancer among women with a family history of breast cancer that was approximately 50% greater in magnitude than among women without a family history. Additional births after the first birth conveyed little protection for women with a family history. History of benign breast disease, past use of oral contraceptives, and use of postmenopausal hormones showed relative risks that did not differ between women with a family history and those without a family history of the disease. Conclusions: We observed a consistent increase in risk of breast cancer among women with a mother or sister history of the disease that was exacerbated by first pregnancy. Among women with a family history of breast cancer, the adverse effect of pregnancy persisted so that to age 70 years, parous women were at higher risk of breast cancer than nulliparous women. Among women without a family history of the disease, first pregnancy was associated with a smaller increase in risk, and early pregnancy and higher number of births were each associated with reduced breast cancer incidence.

A Prospective Study of Coffee Drinking and Suicide in Women

Abstract: Background: Among the many reported central nervous system effects of long-term caffeine use is improvement in mood. Objective: To examine prospectively the relationship of coffee and caffeine intake to risk of death from suicide. Methods: We conducted a 10-year follow-up study (1980 to 1990) in an ongoing cohort of 86 626 US female registered nurses aged 34 to 59 years in 1980, who were free of diagnosed coronary heart disease, stroke, or cancer. Information on coffee and caffeine intake was collected by a semiquantitative food frequency questionnaire in 1980. Deaths from suicide were determined by physician review of death certificates. Results: Fifty-six cases of suicide occurred during 832 704 person-years of observation. Compared with non-drinkers of coffee, the age-adjusted relative risk of suicide in women who consumed two to three cups per day was 0.34 (95% confidence interval [CI], 0.17 to 0.68) and 0.42 (95% CI, 0.21 to 0.86) in women who consumed four or more cups per day (Pfor linear trend=.002). These findings remained essentially unchanged after adjusting for a broad range of potential confounding factors, including smoking habit, alcohol intake, medication use (diazepam and phenothiazine), history of comorbid disease (hypertension, hypercholesterolemia, or diabetes), marital status, and self-reported stress. A strong inverse relationship was similarly found for caffeine intake from all sources and risk of suicide. Conclusions: The data suggest a strong inverse association between coffee intake and risk of suicide. Whether regular intake of coffee or caffeine has clinically significant effects on the maintenance of affect or the prevention of depression merits further investigation in clinical trials and population-based prospective studies. (Arch Intern Med.1996;156:521-525)

Fungus Spores, Air Pollutants, and Other Determinants of Peak Expiratory Flow Rate in Children

Abstract: The impact of summertime haze episodes on daily variations in symptoms and peak expiratory flow rates (PEFRs) was examined in a study of 108 children living in State College, Pennsylvania, during the summer of 1991. Twice daily, each child recorded symptoms, PEFRs and hours spent outdoors. Environmental measurements included daily 12- and 24-hour averages for meteorologic and air pollutant variables and 24-hour average fungus spore concentrations. A 10,000-spore/m3 increment in Cladosporium spore concentration was associated with a deficit in morning PEFR (-1.0 liters/minute, 95% confidence interval (CI) -1.9 to -0.2). A 60-spore/m3 increment in Epicoccum spore concentration was associated with increased incidence of morning cough (odds ratio (OR) = 1.8, 95% CI 1.0-3.2) and a deficit in morning PEFR (-1.5 liters/minute, 95% CI -2.8 to -0.2). Fungi spore counts were not associated with respirable particle mass. A 125-nmol/m3 increment in 12-hour daytime particle-strong acidity was associated with a deficit in evening PEFR (-0.5 liters/minute, 95% CI -1.2 to 0.2) and increased incidence of cold episodes that evening or the subsequent morning (OR = 1.35, 95% CI 1.14-1.61). A 20-microgram/m3 increment in 24-hour respirable particles lagged by 24 hours was associated with a deficit in evening PEFR (-0.5 liters/minute 95% CI -1.4 to 0.4) and increased incidence of cough episodes that evening or the subsequent morning (OR = 1.37, 95% CI 1.13-1.66). These results confirm the acute effects of summertime particulate air pollution and suggest that aeroallergens have independent effects on respiratory symptoms and PEFR in children.

Coffee consumption and coronary heart disease in women. A ten-year follow-up.

Abstract: Objective. —To assess the relationship between coffee consumption and risk of coronary heart disease (CHD) among women. Design. —Prospective cohort study with coffee consumption measured in 1980, 1984, and 1986, and follow-up through 1990. Setting. —Female registered nurses in the United States. Participants. —A total of 85747 US women 34 to 59 years of age in 1980 and without history of CHD, stroke, or cancer. Main Outcome Measure. —Ten-year incidence of CHD (defined as nonfatal myocardial infarction or fatal CHD). Results. —During 10 years of follow-up we documented 712 cases of CHD. After adjustment for age, smoking, and other CHD risk factors, we found no evidence for any positive association between coffee consumption and risk of subsequent CHD. For women drinking six or more cups of caffeine-containing coffee per day in 1980, the relative risk was 0.95 (95% confidence interval, 0.73 to 1.26) compared with women who did not consume this beverage. Similarly, there was no association when the first 4 years of follow-up were excluded, when nonfatal and fatal CHD end points were examined separately, or when we updated coffee consumption in 1984 or 1986 and examined only CHD during the next 2-year interval. Further, there was no association with caffeine intake from all sources combined or with decaffeinated coffee consumption. Conclusions. —These data indicate that coffee as consumed by US women is not an important cause of CHD. ( JAMA . 1996;275:458-462)

Health effects of acid aerosols on North American children: air pollution exposures.

Abstract: Air pollution measurements were conducted over a 1-year period in 24 North American communities participating in a respiratory health study. Ozone, particle strong acidity, sulfate, and mass (PM10 and PM2.1) were measured in all communities. In 20 of the communities, sulfur dioxide, ammonia, nitric acid, nitrous acid, and particulate nitrate were measured. The sampler was located centrally in the community whenever possible and samples were collected every other day. Concentrations of particle strong acidity, mass, sulfate, and ozone were highly correlated both in the region of the country defined as a high-sulfur source area and in the downwind transport regions. These regions of the eastern United States and southern Canada experienced the greatest particle strong acidity, sulfate, and particle mass concentrations during the spring and summer months (May-September). The particle strong acidity concentrations were highest in regions close to the high sulfur emission areas of the United States; that is, in the area immediately to the west of the Appalachian Plateau and west of the Allegheny Mountains (western Pennsylvania, eastern Ohio, and West Virginia) up through southern Ontario. The frequency of particle strong acidity events decreased with transport distance from the region of highest sulfur emissions. Low particle strong acidity and sulfates were found at the western and midwestern sites of both the United States and Canada. Substantial concentrations of nitric acid were found in two of the California sites as well as many sites in the northeastern portion of the United States. Sites selected for the epidemiologic study provide a range of annual mean particle strong acidity exposures from below the limit of detection to more than 50 nmol/m3.

Race, asthma, and persistent wheeze in Philadelphia schoolchildren.

Abstract: OBJECTIVES: Many studies show asthma to be more common in Black than in White children This study assessed how much of this difference remains after adjustment for other potentially race-associated predictors of asthma METHODS: We assessed the predictors of active diagnosed asthma and persistent wheeze in 1416 Black and White Philadelphia children aged 9 to 11 years, as reported by parents RESULTS: Black race remained a significant predictor of active diagnosed asthma (odds ratio [OR] = 23; 95% confidence interval [CI] = 13, 41) but not of persistent wheeze (OR = 10; 95% CI = 06, 18) The excess risk of asthma in Black children was not appreciably altered by adjustment for other demographic and environmental factors CONCLUSIONS: Black race is an important risk factor for active diagnosed asthma in these urban children, a relationship not explained by social factors This finding and the lack of an association of race with persistent wheeze after adjustment for social factors suggest that race ma

Hair dye use and the risk of developing systemic lupus erythematosus: A cohort study

Abstract: Objective. To investigate the role of hair dye use in the etiology of systemic lupus erythematosus (SLE). Methods. Participants included 106,391 women enrolled in the Nurses' Health Study, a prospective cohort study. The subjects were ages 30–55 years in 1976, and were free from SLE and any other connective tissue disease at the time of enrollment. In 1976, 1978, 1980, and 1982, subjects were classified as never-users or ever-users of permanent hair dye, based on self-report. Incidence rates of SLE meeting American College of Rheumatology classification criteria were ascertained and confirmed by chart review. Results. Compared with never-users of permanent hair dye, the age-adjusted relative risks (RR) for the development of SLE among ever-users (n = 85 cases) was 0.96 (95% confidence interval [95% CI] 0.63–1.47). Duration of hair dye use was not related to risk of SLE. Women with 15 or more years of use had no increased risk (RR = 0.92, 95% CI 0.46–1.83). There was no relationship between frequency of use or time since first use and risk of SLE. The results were similar when less stringent criteria for SLE were used. Conclusion. We found no evidence that permanent hair dye use, age at first use, frequency of use, or duration of use is associated with the development of SLE.

Toenail Trace Element Levels and Breast Cancer: A Prospective Study

Abstract: The associations between toenail levels of five trace elements and breast cancer risk were studied among a cohort of 62,641 US women who provided toenail clippings and were free from diagnosed breast cancer in 1982. Among 433 cases of breast cancer identified during 4 years of follow-up and their matched controls, the odds ratios comparing the highest with the lowest quintiles and adjusted for established breast cancer risk factors were as follows : for arsenic, 1.12 (95% confidence interval (CI) 0.66-1.91) ; for copper, 0.91 (95% CI 0.59-1.42) ; for chromium, 0.96 (95% CI 0.61-1.52) ; for iron, 0.89 (95% CI 0.56-1.40) ; and for zinc, 1.09 (95% CI 0.70-1.70). Among postmenopausal women, a marginally significant positive association was observed between toenail chromium levels and breast cancer risk (odds ratio = 1.71, 95% CI 0.87-3.35) (p for trend = 0.07). However, the association between chromium and breast cancer risk was inverse among premenopausal women. Although data on the validity of toenail levels of certain of these elements are limited, these results do not provide evidence for an important effect of arsenic, copper, chromium, iron, or zinc on breast cancer risk.

Passive respiratory mechanics in healthy infants: Effects of growth, gender, and smoking

Abstract: This investigation characterizes the normal growth, variability, and effects of gender and smoking on passive respiratory mechanics in healthy infants. Passive respiratory mechanics were assessed at 193 test sessions on 127 infants (55 boys, 72 girls) between 2 wk and 18 mo of age using the single-occlusion passive flow-volume technique. Respiratory compliance (Crs) increased significantly with increasing infant length, whereas respiratory resistance (Rrs) declined. No significant gender differences were apparent for Crs, although there was a tendency for this measure to be both lower at birth and increase at a slower rate in girls than in boys. Rrs was significantly higher at birth in infant boys than in infant girls, but the rate of the normal decline in Rrs during the first 18 mo also occurred at a significantly greater rate in boys. The passive respiratory time constant (Trs) overall showed little change over this age range, but it was both lower near birth and increased at a significantly greater rate versus infant length in girls than in boys. Maternal smoking during pregnancy was associated with lower levels of Rrs at birth, as well as with significantly slower growth of Crs and natural decline of Rrs in the first 18 mo of life. These data suggest that infant girls may have more mature respiratory mechanics at birth, but that postnatal growth/maturation may be faster in boys.

Airways Responsiveness, Wheeze Onset, and Recurrent Asthma Episodes in Young Adolescents The East Boston Childhood Respiratory Disease Cohort

Abstract: To describe the role of airways responsiveness in predicting incidence of wheeze in early adolescence and to examine the association between airways responsiveness and active asthma symptoms, children who had been tested for airways hyperresponsiveness were assessed prospectively. Of 770 children in the East Boston Childhood Respiratory Disease Cohort who were between 5 and 9 yr of age at time of entry into the study, 281 children received airways challenges during voluntary follow-up conducted between 1980 and 1986. Each subject presented a sequence of wheeze or asthma diagnosis reports along with a sequence of time-varying covariates, including airways challenge results and symptom and exposure information. A robust "pooled repeated observations" analog of the proportional hazard regression model was used to assess associations among risk factors and the probability of incident wheeze or active asthma. In the analysis of wheeze incidence, airways responsiveness (elicited via eucapnic hyperventilation with cold air or methacholine challenge) among those free of a history of wheeze at a given visit was found to be associated with a greater tendency to develop wheezing in the next visit (odds ratio [OR] = 3.91, 95% confidence interval [CI] = 1.21, 12.66), after controlling for a constellation of known risk factors. In the analysis of recurrent asthma episodes, airways responsiveness at a given visit was associated with a greater tendency to have an asthma diagnosis reported at the subsequent visit (OR = 4.2, 95% CI = 1.92, 9.23). For subjects presenting multiple airways responsiveness challenge studies, two successive positive airways responsiveness results were independently associated with a higher likelihood of recurrent asthma episodes. These results confirm the predictive importance of airways responsiveness in the natural history of the development and persistence of asthmatic symptoms.

Respiratory Symptoms in Urban Hispanic and Non-Hispanic White Women

Abstract: The prevalence and predictors of wheeze syndromes, including asthma, were examined among 475 non-Hispanic (NH) white and 371 Hispanic pregnant women enrolled in a population-based study in East Boston, Massachusetts. Respiratory symptoms and risk factors were ascertained by questionnaire early in pregnancy. Hispanic and NH white women were of similar age (mean +/- SD, 26 +/- 5 yr), but Hispanics reported less schooling (30 versus 50% completed high school), a lower frequency of household pets (4 versus 47%), and a lower frequency of parental asthma (6 versus 12%). Hispanics smoked significantly less than NH whites did, both in prevalence (8 versus 50%) and number of cigarettes per day among current smokers (12 +/- 9 versus 22 +/- 10; p < 0.0001). Hispanics reported a lower frequency than NH whites did of doctor-diagnosed asthma (6 versus 12%), persistent wheeze (5 versus 19%), and either persistent wheeze or asthma (11 versus 30%). In multivariate analysis, active cigarette smoking and parental history of asthma were associated most strongly with wheeze syndromes. When these two factors as well as educational level, presence of household pets, and height2-adjusted FEV1 were controlled, Hispanics remained at lower risk of asthma (odds ratio [OR] 0.71; 95% confidence interval [CI], 0.37-1.37) and persistent wheeze (OR 0.48; 95% CI, 0.25-0.95) than NH whites. These results suggest that chronic wheeze syndromes are common among young urban women and are associated with both active smoking and a parental history of asthma. Hispanic women from Central and South America living in urban environments in the United States may be at less risk for these conditions than NH white women, in contrast to those from Puerto Rico.