A prospective study of body mass index and mortality in Bangladesh.
BACKGROUND
Body mass index (BMI) (kg/m(2)) has a U- or J-shaped relationship with all-cause mortality in Western and East Asian populations. However, this relationship is not well characterized in Bangladesh, where the BMI distribution is shifted towards lower values.


METHODS
Using data on 11,445 individuals (aged 18-75 years) participating in the Health Effects of Arsenic Longitudinal Study (HEALS) in Araihazar, Bangladesh, we prospectively examined associations of BMI (measured at baseline) with all-cause mortality during approximately 6 years of follow-up. We also examined this relationship within strata of key covariates (sex, age, smoking, education and arsenic exposure). Cox proportional hazards models adjusted for these covariates and BMI-related illnesses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for BMI categories defined by the World Health Organization.


RESULTS
Low BMI was strongly associated with increased mortality in this cohort (P-trend < 0.0001). Severe underweight (BMI < 16 kg/m(2); HR 2.06, CI 1.53-2.77) and moderate underweight (16.0-16.9 kg/m(2); HR 1.39, CI 1.01-2.90) were associated with increased all-cause mortality compared with normal BMI (18.6-22.9 kg/m(2)). The highest BMI category (> or =23.0 kg/m(2)) did not show a clear association with mortality (HR 1.10, CI 0.77-1.53). The BMI-mortality association was stronger among individuals with <5 years of formal education (interaction P = 0.02).


CONCLUSIONS
Underweight (presumably due to malnutrition) is a major determinant of mortality in the rural Bangladeshi population.
Pierce
Brandon L
BL
Department of Health Studies, The University of Chicago, Chicago, IL 60637, USA.
Kalra
Tara
T
Argos
Maria
M
Parvez
Faruque
F
Chen
Yu
Y
Islam
Tariqul
T
Ahmed
Alauddin
A
Hasan
Rabiul
R
Rakibuz-Zaman
Muhammad
M
Graziano
Joseph
J
Rathouz
Paul J
PJ
Ahsan
Habibul
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D001459:Bangladesh / Q000453:epidemiology; D015992:Body Mass Index; D002423:Cause of Death; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data; D013851:Thinness / Q000401:mortality*; D055815:Young Adult