Department of Community and Family Medicine, Duke University Medical Centre, Durham, NC, USA.
Int J Epidemiol. 2011 Feb;40(1):240-50. doi: 10.1093/ije/dyq142. Epub 2010 Sep 5.
Most studies describing change in body mass through adulthood model an 'average' trajectory bearing the same functional form in the underlying population. Latent-class growth modelling has revealed the presence of several underlying body mass/obesity trajectory groups among children and adolescents, but has not been applied to capture adult body mass trajectories. We apply the technique to identify adult body mass trajectory groups, risk factors for group membership and (time-varying) modifiers of trajectory level within each group, and assess association between group membership and important health outcomes in midlife.
Body mass trajectory groups, from age 18 to 49 years, were identified using latent-class growth modelling based on the National Longitudinal Survey of Youth 1979 (n = 9681). Role of gender, race/ethnicity and age cohort as risk factors for group membership, and of highest grade of education completed, years of urban living, years in employment, years in poverty and years married as modifiers of trajectory level was evaluated.
Four trajectory groups, 'normal weight', 'overweight', 'late adulthood obesity' and 'early adulthood obesity' were identified. Males, Blacks and those born later had higher odds of being in the three latter groups. More education and years married lowered the trajectory within each group. The prevalence of most health outcomes was lowest in the 'normal weight' group, somewhat greater in the 'overweight' group, greater again in the 'late adult obesity group' and highest in the 'early adulthood obesity' group.
Regular body mass index screening and monitoring in early adult life may identify a person as belonging to one of these four groups early, and allow the individual and health-care providers opportunities to initiate behavioural or other interventions better tailored to the specific group.
大多数描述成年人身体质量变化的研究都是通过模型来描述一个“平均”轨迹，该轨迹在基础人群中具有相同的功能形式。潜在类别增长建模已经揭示了儿童和青少年中存在几种潜在的身体质量/肥胖轨迹群体，但尚未应用于捕获成年人体质量轨迹。我们应用该技术来识别成年人体质量轨迹群体、群体成员的风险因素以及每个群体中轨迹水平的（时变）修饰符，并评估群体成员与中年重要健康结果之间的关联。
使用基于国家青年纵向调查 1979 年（n=9681）的潜在类别增长建模来确定从 18 岁到 49 岁的人体质量轨迹群体。评估性别、种族/族裔和年龄队列作为群体成员的风险因素，以及最高完成的教育程度、在城市居住的年数、就业年数、贫困年数和结婚年数作为轨迹水平修饰符的作用。
确定了四个轨迹群体，“正常体重”、“超重”、“成年后期肥胖”和“成年早期肥胖”。男性、黑人以及出生较晚的人更有可能属于后三组。更多的教育和结婚年限降低了每个群体的轨迹。大多数健康结果的患病率在“正常体重”组中最低，在“超重”组中稍高，在“成年后期肥胖”组中更高，在“成年早期肥胖”组中最高。
在成年早期定期进行身体质量指数筛查和监测可能会及早识别一个人属于这四个群体之一，并为个人和医疗保健提供者提供机会，以便针对特定群体更好地启动行为或其他干预措施。
