Slowing down of adult body mass index trend increases in England: a latent class analysis of cross-sectional surveys (1992–2010)

• Published in: International Journal of Obesity Vol. 38; no. 6; pp. 818 - 824
• Main Authors: Sperrin, M, Marshall, A D, Higgins, V, Buchan, I E, Renehan, A G
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2014; Nature Publishing Group
• Subjects: 692/700/139/2818; 692/700/478; Adult; Age; Aged; Biological and medical sciences; Body Composition; Body Mass Index; Body size; Body weight; Cross-Sectional Studies; England - epidemiology; Epidemiology; Female; Forecasts and trends; Gender; Health Promotion and Disease Prevention; Health Surveys; Humans; Internal Medicine; Latent class analysis; Linear Models; Male; Mean; Medical research; Medical sciences; Medicine; Medicine & Public Health; Medicine, Experimental; Men; Metabolic Diseases; Middle Aged; Miscellaneous; Obesity; Obesity - epidemiology; original-article; Polls & surveys; Population; Populations; Prevalence; Probabilistic models; Public Health; Public health. Hygiene; Public health. Hygiene-occupational medicine; Regression analysis; Regression models; Risk factors; Subgroups; Trends; Women; Womens health; England; United Kingdom; Great Britain; Europe; United Kingdom > UK; United States > US; latent class analysis; body mass index; trends; Health Survey of England; Human; Obesity; Statistical analysis; Nutrition; Nutrition disorder; Trend; Metabolic diseases; Increase; Latent class analysis; Body mass index; Survey; Health status; Surveillance; 1992; Cross sectional study; Adult; Nutritional status; Public health
• ISSN: 0307-0565; 1476-5497; 1476-5497
• DOI: 10.1038/ijo.2013.161

Background: 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. Objective: We address the hypothesis that the slowing down of BMI trend increases in England reflects a majority sub-population resistant to further BMI elevation. Design: 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. Subjects: BMI was available for 164 155 adults (men: 76 382; women: 87 773). Results: 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). Conclusion: 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.