Body Weight and Mortality Among Adults Who Never Smoked
Most prospective studies identify an increased mortality risk for adults of high body mass index (> 27 kg/m2) that is commonly attributed to the effects of excess body fat, and also identify an increased mortality risk for adults of low body mass index (< 21 kg/m2), an association that, if causal among healthy adults, is without adequate pathophysiologic support. In this dissertation, I have conducted three studies that continue the investigation of adiposity in relation to mortality among never-smoking adults of the California Seventh-day Adventist population. Among never-smoking adults of the Adventist Mortality Study (1960-1985), the relation between body mass index (BMI) and all-cause mortality has been examined and the investigators found a direct positive relation among middle-aged men, older men, and middle-aged women, and a J-shaped relation among older women. In the first study, I found that among 12,576 never-smoking women of the Adventist Mortality Study, the risk due to high BMI (> 27 kg/m2) was primarily due to cardiovascular disease and the risk due to low BMI (< 21 kg/m2) among older women was primarily due to cardiovascular and respiratory diseases. In the second study, I examined the relation between BMI and mortality among 20,346 never-smoking adults of the Adventist Health Study (1976-1988) and found a direct positive relation among middle-aged men, older men, middle-aged women, and a J-shaped relation among older women. Further study of the older women indicated that increased risk due to the lowest BMI (13.4-20.6 kg/m2) was only evident among those who had not used hormone replacement therapy, and that this risk was primarily due to cardiovascular and respiratory disease. In the third study, I related weight gain over a 17-year interval to all cause mortality among 6,030 never-smoking members of the 1960 and 1976 cohorts and found evidence implicating weight gain (> 10 kg) as a risk factor and that this risk remained evident for weight gains recorded at the sixth, seventh, and eighth decade. The findings from these studies implicate obesity as a risk factor throughout adulthood and raise the possibility that lean older women can experience an increased mortality risk that may be due to their lower levels of adipose tissue-derived estrogens.
Biostatistics, Epidemiology, Vital and Health Statistics, Body Weight; Obesity -- mortality; Smoking; Health Status Indicators; Health Surveys; Mortality.
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