Body Size and Metabolic Health: A Phenotypic Characterisation of an Indigenous African Working Population

Abstract

Background: An obesity subgroup has been described that do not have the typical metabolic abnormalities associated with obesity. Aims: We characterized body size and metabolic phenotypes among public employees. Materials and methods: 879 participants were evaluated using WHO-STEP wise approach to non-communicable diseases screening. Body size was classed according to WHO guidelines. Metabolically healthy obesity (MHO) was defined as obesity without elevated blood pressure, diabetes mellitus and reduced HDL-C (< 40mg/ dl for men and<50 mg/dl for women respectively). Determinants of MHO were assessed in a logistic regression model adjusting for socio-demographic, clinical and biochemical variables. Results: 38.1% (335/879) had normal BMI, 35.5% (312/879) were overweight and 26.4% (232/879) were obese. The prevalence of metabolically healthy normal weight (MHNW), metabolically healthy overweight (MHOWT) and metabolically healthy obese (MHO) was 47.7% (160/335), 32.6% (102/312) and 18.5% (43/232) respectively (p<0.001). Tertiary education (adjusted odds ratio (AOR)=1.59; 95% CI: 1.03-2.47), hypertension (AOR=2.30; 95% CI: 1.58-3.35), hypercholesterolaemia (AOR=1.52; 95% CI: 1.06-2.17) and reduced HDL-C (AOR=2.40; 95% CI: 1.20-4.78) independently predicted generalized obesity, while male sex (AOR=0.10, 95% CI: 0.07- 0.16) reduced the risk of generalized obesity by 90%. Age 45 years and older (AOR=0.29; 95% CI: 0.20-0.40, p<0.001), alcohol intake (AOR=0.50; 95% CI: 0.34-0.74, p<0.001), and generalized obesity (AOR=0.31; 95% CI: 0.20-0.47, p<0.001) were protective against MHO. Conclusion: A significant proportion of the participants had the MHO phenotype. Body size had an inverse relationship with metabolic health.