|NCD Risk Factor Collaboration (NCD-RisC) (2017) Worldwide trends in body-mass index, underweight, overweight, and obesity from 1975 to 2016: a pooled analysis of 2416 population-based measurement studies in 128·9 million children, adolescents, and adults. Lancet 390:2627–42.|
Abstract: BACKGROUND: Underweight, overweight, and obesity in childhood and adolescence are associated with adverse health consequences throughout the life-course. Our aim was to estimate worldwide trends in mean body-mass index (BMI) and a comprehensive set of BMI categories that cover underweight to obesity in children and adolescents, and to compare trends with those of adults.
METHODS: We pooled 2416 population-based studies with measurements of height and weight on 128·9 million participants aged 5 years and older, including 31·5 million aged 5-19 years. We used a Bayesian hierarchical model to estimate trends from 1975 to 2016 in 200 countries for mean BMI and for prevalence of BMI in the following categories for children and adolescents aged 5-19 years: more than 2 SD below the median of the WHO growth reference for children and adolescents (referred to as moderate and severe underweight hereafter), 2 SD to more than 1 SD below the median (mild underweight), 1 SD below the median to 1 SD above the median (healthy weight), more than 1 SD to 2 SD above the median (overweight but not obese), and more than 2 SD above the median (obesity).
FINDINGS: Regional change in age-standardised mean BMI in girls from 1975 to 2016 ranged from virtually no change (-0·01 kg/m2 per decade; 95% credible interval -0·42 to 0·39, posterior probability [PP] of the observed decrease being a true decrease=0·5098) in eastern Europe to an increase of 1·00 kg/m2 per decade (0·69-1·35, PP>0·9999) in central Latin America and an increase of 0·95 kg/m2 per decade (0·64-1·25, PP>0·9999) in Polynesia and Micronesia. The range for boys was from a non-significant increase of 0·09 kg/m2 per decade (-0·33 to 0·49, PP=0·6926) in eastern Europe to an increase of 0·77 kg/m2 per decade (0·50-1·06, PP>0·9999) in Polynesia and Micronesia. Trends in mean BMI have recently flattened in northwestern Europe and the high-income English-speaking and Asia-Pacific regions for both sexes, southwestern Europe for boys, and central and Andean Latin America for girls. By contrast, the rise in BMI has accelerated in east and south Asia for both sexes, and southeast Asia for boys. Global age-standardised prevalence of obesity increased from 0·7% (0·4-1·2) in 1975 to 5·6% (4·8-6·5) in 2016 in girls, and from 0·9% (0·5-1·3) in 1975 to 7·8% (6·7-9·1) in 2016 in boys; the prevalence of moderate and severe underweight decreased from 9·2% (6·0-12·9) in 1975 to 8·4% (6·8-10·1) in 2016 in girls and from 14·8% (10·4-19·5) in 1975 to 12·4% (10·3-14·5) in 2016 in boys. Prevalence of moderate and severe underweight was highest in India, at 22·7% (16·7-29·6) among girls and 30·7% (23·5-38·0) among boys. Prevalence of obesity was more than 30% in girls in Nauru, the Cook Islands, and Palau; and boys in the Cook Islands, Nauru, Palau, Niue, and American Samoa in 2016. Prevalence of obesity was about 20% or more in several countries in Polynesia and Micronesia, the Middle East and north Africa, the Caribbean, and the USA. In 2016, 75 (44-117) million girls and 117 (70-178) million boys worldwide were moderately or severely underweight. In the same year, 50 (24-89) million girls and 74 (39-125) million boys worldwide were obese.
INTERPRETATION: The rising trends in children's and adolescents' BMI have plateaued in many high-income countries, albeit at high levels, but have accelerated in parts of Asia, with trends no longer correlated with those of adults.
• Bioblast editor: Gnaiger E
|Healthy reference population||Body mass excess||BFE||BME cutoffs||BMI||H||M||VO2max||mitObesity drugs|
From BMI to BME
- It is widely agreed upon that conventional BMI cutoffs at 25 and 30 kg·m-2 for overweight and obese, respectively, need to be adjusted downwards in Asian populations. The WHO Expert Consultation (2004) concluded, however, that 'available data do not necessarily indicate a clear BMI cut-off point for all Asians for overweight or obesity. The cut-off point for observed risk varies from 22 kg/m2 to 25 kg/m2 in different Asian populations; for high risk it varies from 26 kg/m2 to 31 kg/m2.' No rationale was provided for country- or population-specific cutoffs. The concept of the healthy reference population, reference body mass, M°, for a given height, and the relative body mass excess, BME, provide a concept for 'personalized' cutoffs. Although the BME can replace the BMI, harmonization with the vast literature on BMI can be achieved by expressing anthropometric data both in terms of BME and BME-derived personalized BMI cutoffs.
- The reference body mass, M°, is calculated for height, H>1.23 m, as
M° = 12.68·H2.857
- The personal critical mass for overweight, 1.2M°, and obese, 1.4M° are,
1.2M° = 1.2·M° 1.4M° = 1.4·M°
- The BMI1.2 is the personal cutoff for overweight, and the BMI1.4 is the personal cutoff for obese,
BMI1.2 = 1.2M°/H2 BMI1.4 = 1.4M°/H2
The BME-derived personal BMI-cutoffs are higher for men than women due to the average difference of 0.12 m in heights, and predict trends of various adjustments in BMI-cutoffs of Asian populations. In addition, the BME-derived personal BMI-cutoffs provide a unifying approach for anthropometric comparison of children, adolescents and adults (see De Onis et al 2007).
- NCD Risk Factor Collaboration (NCD-RisC) (2017) Worldwide trends in body-mass index, underweight, overweight, and obesity from 1975 to 2016: a pooled analysis of 2416 population-based measurement studies in 128·9 million children, adolescents, and adults. Lancet 390:2627–42.
- NCD Risk Factor Collaboration (NCD-RisC) (2016) A century of trends in adult human height. Elife 5 pii: e13410. doi: 10.7554/eLife.13410. - »Bioblast link«
- WHO Expert Consultation (2004) Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 363:157-63. - »Bioblast link«
- de Onis M, Onyango AW, Borghi E, Siyam A, Nishida C, Siekmann J (2007) Development of a WHO growth reference for school-aged children and adolescents. Bull World Health Organization 85:660-7. - »Bioblast link«
- Body mass excess
Labels: MiParea: Gender, Developmental biology, Exercise physiology;nutrition;life style Pathology: Obesity
Preparation: Intact organism