General and abdominal adiposity and hypertension in eight world regions: a pooled analysis of 837 population-based studies with 7·5 million participants

Background Adiposity can be measured using BMI (which is based on weight and height) as well as indices of
abdominal adiposity. We examined the association between BMI and waist-to-height ratio (WHtR) within and across
populations of different world regions and quantified how well these two metrics discriminate between people with
and without hypertension.
Methods We used data from studies carried out from 1990 to 2023 on BMI, WHtR and hypertension in people aged
20–64 years in representative samples of the general population in eight world regions. We graphically compared the
regional distributions of BMI and WHtR, and calculated Pearson’s correlation coefficients between BMI and WHtR
within each region. We used mixed-effects linear regression to estimate the extent to which WHtR varies across
regions at the same BMI. We graphically examined the prevalence of hypertension and the distribution of people who
have hypertension both in relation to BMI and WHtR, and we assessed how closely BMI and WHtR discriminate
between participants with and without hypertension using C-statistic and net reclassification improvement (NRI).
Findings The correlation between BMI and WHtR ranged from 0·76 to 0·89 within different regions. After adjusting
for age and BMI, mean WHtR was highest in south Asia for both sexes, followed by Latin America and the Caribbean
and the region of central Asia, Middle East and north Africa. Mean WHtR was lowest in central and eastern Europe
for both sexes, in the high-income western region for women, and in Oceania for men. Conversely, to achieve an
equivalent WHtR, the BMI of the population of south Asia would need to be, on average, 2·79 kg/m² (95% CI
2·31–3·28) lower for women and 1·28 kg/m² (1·02–1·54) lower for men than in the high-income western region. In
every region, hypertension prevalence increased with both BMI and WHtR. Models with either of these two adiposity
metrics had virtually identical C-statistics and NRIs for every region and sex, with C-statistics ranging from
0·72 to 0·81 and NRIs ranging from 0·34 to 0·57 in different region and sex combinations. When both BMI and
WHtR were used, performance improved only slightly compared with using either adiposity measure alone.
Interpretation BMI can distinguish young and middle-aged adults with higher versus lower amounts of abdominal
adiposity with moderate-to-high accuracy, and both BMI and WHtR distinguish people with or without hypertension.
However, at the same BMI level, people in south Asia, Latin America and the Caribbean, and the region of central
Asia, Middle East and north Africa, have higher WHtR than in the other regions