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标题：Body Mass Index and Disability in Adulthood: A 20-Year Panel Study
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作者：Kenneth F. Ferraro ; Ya-ping Su ; Randall J. Gretebeck 等
期刊名称：American journal of public health
印刷版ISSN：0090-0036
出版年度：2002
卷号：92
期号：5
页码：834-840
语种：English
出版社：American Public Health Association
摘要：Objectives. This study examined whether body mass index (BMI) or change in BMI raises the risk of disability in adulthood. Methods. The relation between BMI and upper- and lower-body disability was examined among adult subjects from a national longitudinal survey (n = 6833). Tobit regression models were used to examine the effect of BMI on disability 10 and 20 years later. Results. Obesity (BMI ≥ 30) at baseline or becoming obese during the study was associated with higher levels of upper- and, especially, lower-body disability. In persons who began the study with a BMI of 30 or more and became normal weight, disability was not reduced. Underweight persons (BMI < 18.5) also manifested higher disability in most instances. Conclusions. Disability risk was higher for obese persons, but overweight was not consistently associated with higher disability. The link between body weight and both morbidity and mortality has been examined extensively, but relatively little research has investigated the relation between body weight and disability. 1 Among the studies that have investigated this relation, the findings are inconsistent. Some of these studies showed that body weight is related to functional disability, 2– 8 whereas others found no such link. 9, 10 Although the inconsistency may be a result of different research designs and analytic approaches, the measurement of both disability and body weight may be partly responsible for the discrepant findings. First, disability is defined here as a restriction or lack of ability to perform an activity in any domain of life. 11, 12 Although it may be helpful in some circumstances to consider a global construct of overall disability, most of the literature has moved to defining domains of disability, such as upper- and lower-body disability, to better elucidate the process of disablement. 9, 13– 15 In addition, the literature suggests a hierarchy in the disablement process such that many of the lower-body or mobility functions, including balance and lower-extremity strength, are the most difficult to maintain, whereas upper-body functions, such as manual dexterity and upper-extremity strength, are easier to maintain. 13, 14 Thus, studies that combine various domains of disability into a single global construct 10 or that consider only a limited range of activities 9 may not be as likely as other studies to uncover a link. Some evidence indicates that obesity is associated with a greater risk for both lower-body 16, 17 and upper-body osteoarthritis 18 leading to disability, but the relation between body weight and different domains of disability must be systematically and longitudinally studied. Second, the measurement of body weight may itself contribute to inconsistent findings. One empirical generalization that may be gleaned from the studies that found a link between body weight and disability is that the relation is not linear. Rather, similar to the findings on body mass index (BMI) and mortality, most studies find that the extremes of the BMI distribution are associated with higher disability. 2, 4, 5 If only a linear relation between BMI and disability were considered, then the effects associated with low and high BMI would cancel each other, especially when studying an older adult population. The reasons that obesity and underweight are related to disability are probably a result of different mechanisms. Obesity in adulthood may lead to disability because of 1 or more biological processes: skeletal stress, 19 protein glycation in connective tissue, 20, 21 or atherogenesis. 22 Underweight in adulthood, on the contrary, is more often the result of disability, especially among older people. 23– 25 In more developed countries, underweight is likely the result of disablement processes whereby disease progression during terminal illness leads to reduced muscle mass and strength. 26 (Although weight gain is common in middle age, weight loss is common in advanced ages. 7 ) The current study systematically examined the relation between BMI and upper- and lower-body disability in a longitudinal study. We anticipated that both obese and underweight persons would manifest higher levels of both types of disability but that the relations would be stronger for lower-body disability. 8, 27, 28 Although it is unclear if overweight also raises disability risk, such an effect was tested with the National Heart, Lung, and Blood Institute (NHLBI) guidelines. 29 Our findings should enhance epidemiological knowledge of BMI and disability risk, including the utility of the NHLBI guidelines for such analyses, and be helpful for health policy and health education efforts to minimize disability in American society.