Prevalence and correlates of diabetes mellitus in Malawi: population-based national NCD STEPS survey

Background: Previously considered as a disease of the affluent, west or urban people and not of public health importance, diabetes mellitus is increasingly becoming a significant cause of morbidity and mortality in sub-Saharan Africa. However, population-based data to inform prevention, treatment and control are lacking. Methods: Using the WHO STEPwise approach to chronic disease risk factor surveillance, a population-based, nationwide cross-sectional survey was conducted between July and September 2009 on participants aged 25-64 years. A multi-stage cluster sample design and weighting were used to produce a national representative data for that age range. Detailed findings on the magnitude of diabetes mellitus and impaired fasting blood glucose are presented in this paper. Results: Fasting blood glucose measurement was conducted on 3056 participants (70.2% females, 87.9% from rural areas). The age-sex standardised population-based mean fasting blood glucose was 4.3 mmol/L (95% CI 4.1-4.4 mmol/L) with no significant differences by age, sex and location (urban/rural). The overall prevalence of impaired fasting blood glucose was 4.2% (95% CI 3.0%-5.4%). Prevalence of impaired blood glucose was higher in men than in women, 5.7% (95% CI 3.9%-7.5%) vs 2.7% (95% CI 1.6%-3.8%), p < 0.01. In both men and women, prevalence of raised fasting blood glucose or currently on medication for diabetes was 5.6% (95% CI 2.6%-8.5%). Although the prevalence of diabetes was higher in men than women, 6.5% (95% CI 2.6%-10.3%) vs 4.7% (95% CI 2.4%-7.0%), in rural than urban, 5.4% (95% CI 2.4%-8.4%) vs 4.4% (95% CI 2.8%-5.9%) and in males in rural than males in urban, 6.9% (95% CI 2.8%-11.0%) vs 3.2% (95% CI 0.1%-6.3%), the differences were not statistically significant, p > 0.05. Compared to previous estimates, prevalence of diabetes increased from < 1.0% in 1960s to 5.6% in 2009 (this study). Conclusion: High prevalence of impaired fasting blood glucose and diabetes mellitus call for the implementation of primary healthcare approaches such as the WHO package for essential non-communicable diseases to promote healthy lifestyles, early detection, treatment and control.