Trends in adult body-mass index in 200 countries from 1975 to 2014: a pooled analysis of 1698 population-based measurement studies with 19·2 million participants.
Level 1 - systematic review of randomized trials
Systematic pooled meta-analysis and global epidemiological modeling of 1,698 population-based studies (by design analogy, not clinical CEBM).
PubMed 27115820 · doi:10.1016/S0140-6736(16)30054-X
What was done
The authors analysed 1,698 population-based measurement studies of height and weight covering >19.2 million adults aged 18 years and older across 186 of 200 countries and territories. A Bayesian hierarchical model was applied to estimate trends from 1975 to 2014 in age-standardised mean body-mass index (BMI) and seven BMI categories (from <18.5 kg/m² to ≥40 kg/m²) across 21 world regions by sex. They also estimated the posterior probability of meeting the global target of halting obesity rise at 2010 levels by 2025.
What was found
Global age-standardised mean BMI increased from 21.7 kg/m² (95% CrI 21.3–22.1) in 1975 to 24.2 kg/m² (24.0–24.4) in 2014 in men, and from 22.1 kg/m² (21.7–22.5) to 24.4 kg/m² (24.2–24.6) in women. Age-standardised obesity prevalence rose from 3.2% (2.4–4.1) to 10.8% (9.7–12.0) in men and from 6.4% (5.1–7.8) to 14.9% (13.6–16.1) in women. Severe obesity (BMI ≥35 kg/m²) reached 2.3% in men and 5.0% in women, while morbid obesity (BMI ≥40 kg/m²) reached 0.64% in men and 1.6% in women. Underweight prevalence declined globally from 13.8% to 8.8% in men and 14.6% to 9.7% in women, but remained high in South Asia (23.4% in men, 24.0% in women in 2014). The probability of halting the rise in obesity by 2025 was calculated as virtually zero.
Why it matters
This study provides comprehensive global surveillance showing an accelerating shift toward severe obesity alongside persistent undernutrition in the poorest regions. It confirms that without substantial intervention, international targets to curb obesity will not be met.
Limits
Data were available for 186 of 200 evaluated countries, meaning 14 countries relied entirely on statistical imputation from regional models. BMI does not differentiate between lean and adipose tissue or capture body fat distribution. The analysis is limited to adults aged ≥18 years, and future projections rely on the continuation of post-2000 trends.
Cited by
- supports Globally, obesity is now a larger public health problem than undernutrition or malnutrition.