Sperrin M, Marshall A D, Higgins V, Buchan I E, Renehan A G
Institute of Population Health, Medical Research Council Health eResearch Centre (HeRC), University of Manchester, Manchester, UK.
CCSR, School of Social Sciences, University of Manchester, Manchester, UK.
Int J Obes (Lond). 2014 Jun;38(6):818-24. doi: 10.1038/ijo.2013.161. Epub 2013 Sep 2.
The prevalence of excess body weight, commonly measured as body mass index (BMI)≥25 kg m(-2), has increased substantially in many populations worldwide over the past three decades, but the rate of increase has slowed down in some western populations.
We address the hypothesis that the slowing down of BMI trend increases in England reflects a majority sub-population resistant to further BMI elevation.
Pseudo-panel data derived from annual cross-sectional surveys, the Health Surveys for England (1992-2010). Trends in median BMI values were explored using regression models with splines, and gender-specific mixture model (latent class analysis) were fit to take an account of increasing BMI distribution variance with time and identify hidden subgroups within the population.
BMI was available for 164 155 adults (men: 76 382; women: 87 773).
Until 2001, the age-adjusted yearly increases in median BMI were 0.140 and 0.139 kg m(-2) for men and women, respectively, decreasing thereafter to 0.073 and 0.055 kg m(-2) (differences between time periods, both P-values<0.0001). The mixture model identified two components--a normal BMI and a high BMI sub-population--the proportions for the latter were 23.5% in men and 33.7% in women. The remaining normal BMI populations were 'resistant' with minimal increases in mean BMI values over time. By age, mean BMI values in the normal BMI sub-population increased greatest between 20 and 34 years for men; for women, the increases were similar throughout age groups (slope differences, P<0.0001).
In England, recent slowing down of adult BMI trend increases can be explained by two sub-populations--a high BMI sub-population getting 'fatter' and a majority 'resistant' normal BMI sub-population. These findings support a targeted, rather than a population-wide, policy to tackle the determinants of obesity.
过去三十年里，全球许多人群中超重（通常以体重指数（BMI）≥25kg/m²衡量）的患病率大幅上升，但在一些西方人群中，上升速度已有所放缓。
我们探讨这样一种假设，即英国BMI趋势增长放缓反映了大多数亚人群对BMI进一步升高具有抵抗力。
伪面板数据源自年度横断面调查《英格兰健康调查》（1992 - 2010年）。使用带样条的回归模型探索BMI中位数的趋势，并拟合性别特异性混合模型（潜在类别分析），以考虑BMI分布方差随时间的增加，并识别总体中的隐藏亚组。
164155名成年人（男性：76382名；女性：87773名）有BMI数据。
到2001年为止，年龄调整后的BMI中位数年增长率男性为0.140kg/m²，女性为0.139kg/m²，此后分别降至0.073kg/m²和0.055kg/m²（时间段之间的差异，P值均<0.0001）。混合模型识别出两个部分——正常BMI亚人群和高BMI亚人群——后者在男性中的比例为23.5%，在女性中的比例为33.7%。其余正常BMI人群具有“抵抗力”，随着时间推移，其平均BMI值增幅极小。按年龄来看，正常BMI亚人群中男性的平均BMI值在20至34岁之间增长最大；对于女性，各年龄组的增长情况相似（斜率差异，P<0.0001）。
在英国，近期成人BMI趋势增长放缓可由两个亚人群来解释——一个高BMI亚人群变得“更胖”，以及一个占多数的具有“抵抗力”的正常BMI亚人群。这些发现支持采取有针对性而非针对全体人群的政策来应对肥胖的决定因素。
