Biomedical subjects
Publications and source records attributed to Richard S Crow.
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Early life factors may influence pulmonary function. We measured forced expiratory volume in 1 second (FEV(1)) in 1985-1986 and 2, 5, and 10 years later in approximately 4,000 black and white men and women initially aged 18-30 years. We estimated the age pattern of FEV(1) according to family smoking status, early diagnosis of asthma, early smoking initiation, adult asthma, and cigarette smoking. FEV(1) followed a quadratic pattern from age of peak through age 40. The pattern varied by race and sex. Early smoking initiation was associated with a faster decrease in FEV(1). Smoking by family members was related to early life asthma and may have contributed to faster FEV(1) decrease by encouraging behaviors such as heavier smoking or earlier smoking initiation. Prevalence of smoking was 28% when no family member smoked, compared with 59% when four or more members smoked. The FEV(1) decline was 8.5% in never-smokers without asthma; 10.1% in nonsmoking individuals diagnosed with asthma; and 11.1% in baseline smokers who smoked 15 or more cigarettes per day. The combination of asthma and heavier smoking was synergistic (17.8% decline). This study delineates an increased rate of decline in those with asthma or in those who smoke cigarettes and implicates early life exposures as contributing to the faster rate of FEV(1) decline.
BACKGROUND: The distribution or the causes of premature ventricular contractions (PVCs) in diverse populations are not fully known. We describe the prevalence of PVCs on a 2-minute electrocardiogram (ECG) in adults to determine whether hypertension has an important association with such PVCs. METHODS: A cross-sectional analysis of the 15,792 individuals (aged 45-65 years) from the four US communities participating at visit 1 of the Atherosclerosis Risk In Communities (ARIC) study was performed. Multiple logistic regression was used to determine the association of PVCs with potential causal predictors of PVCs. RESULTS: Based on a 2-minute ECG, PVCs are present in >6% of middle-aged adults. Increasing age, the presence of heart disease, faster sinus rates, African American ethnicity, male sex, lower educational attainment, and lower serum magnesium or potassium levels are directly related to PVC prevalence. Independently of these factors, hypertension is associated with a 23% increase in the prevalence of PVCs. CONCLUSIONS: The prevalence of PVCs on a 2-minute ECG differs by age, ethnicity, and sex and is associated with hypertension, heart disease, faster sinus rates, electrolyte abnormalities, and lower educational attainment. Hypertension is likely to be a major cause of PVCs in adults.