摘要：Objectives. We examined the association of body mass index with all-cause and cardiovascular disease (CVD)–specific mortality risks among US adults and calculated the rate advancement period by which death is advanced among the exposed groups. Methods. We used data from the Third National Health and Nutrition Examination Survey (1988–1994) linked to the National Death Index mortality file with follow-up to 2006 (n = 16 868). We used Cox proportional hazards regression to estimate the rate of dying and rate advancement period for all-cause and CVD-specific mortality for overweight and obese adults relative to their normal-weight counterparts. Results. Compared with normal-weight adults, obese adults had at least 20% significantly higher rate of dying of all-cause or CVD. These rates advanced death by 3.7 years (grades II and III obesity) for all-cause mortality and between 1.6 (grade I obesity) and 5.0 years (grade III obesity) for CVD-specific mortality. The burden of obesity was greatest among adults aged 45 to 64 years for all-cause and CVD-specific mortality and among women for all-cause mortality. Conclusions. These findings highlight the impact of the obesity epidemic on mortality risk and premature deaths among US adults. Obesity has been increasing in the US population over the past 5 decades, and so has its impact on morbidity 1–3 and mortality. 4–9 For instance, obesity has been associated with all-cause mortality in the United States and elsewhere. 10–13 In fact, evidence from a recent review of 97 articles (including 37 in the United States) suggests that obesity (body mass index [BMI; defined as weight in kilograms divided by the square of height in meters] ≥ 30.0) is associated with higher all-cause mortality risk. 14 When obesity was further classified into grades I (BMI 30.0 to < 35), II (BMI 35.0 to < 40.0), and III (BMI ≥ 40.0), the high risk of mortality was observed for grades II and III only. By contrast, overweight was associated with a protective effect against all-cause mortality. 14 Moreover, studies examining obesity and CVD-specific mortality have also found a significant increase in mortality risk among US obese adults. 9,15,16 Among studies examining the association between obesity and mortality in the United States, few have focused on a nationally representative sample such as the National Health and Nutrition Examination Survey (NHANES) with objective measures of weight and height, 8,9,17 and none has examined the effect of overweight and obesity on advancing the risk of death among adults. Thus, we used data from the NHANES III for the years 1988 through 1994 linked to the National Death Index (NDI) mortality file with follow-up to year 2006 to examine the association of BMI categories with all-cause and CVD-specific mortality risk among US adults aged 18 years and older. We also calculated the rate advancement period (RAP) 18 or the average time by which the rate of death is advanced among overweight and obese adults compared with their normal-weight counterparts. In addition, we examined whether these associations and RAPs differed by age, gender, and race/ethnicity.
