Weight threshold and blood pressure in a lean black population

Area of Science:

• Cardiovascular Health
• Metabolic Syndrome
• Epidemiology

Background:

• Hypertension prevalence varies significantly across African populations, increasing with weight and Westernization.
• A potential threshold effect of body weight on blood pressure is suggested by population differences.

Purpose of the Study:

• To investigate the relationship between body mass index (BMI) and blood pressure in urban Nigerian civil servants.
• To identify a potential BMI threshold above which blood pressure becomes correlated with weight.

Main Methods:

• Cross-sectional study of 799 urban Nigerian civil servants (500 men, 299 women) in Benin City, 1992.
• Measurements included blood pressure, BMI, fat-related metrics, fasting insulin, physical activity, diet, and electrolyte excretion.
• Analysis involved examining age-adjusted mean blood pressure across BMI quantiles.

Main Results:

• A BMI threshold of 21.5 kg/m² was identified, below which blood pressure was not correlated with BMI.
• Above this threshold, blood pressure was significantly correlated with BMI, even at levels considered lean in other populations.
• Physical activity was higher in men below the BMI threshold; fasting insulin and waist-hip ratio correlated with BMI but not independently with blood pressure.

Conclusions:

• A distinct threshold exists below which body weight has minimal impact on blood pressure.
• Above this threshold, even in lean individuals, weight is a significant determinant of blood pressure in this African population.
• This finding has implications for understanding hypertension in African ancestries, including those in Westernized populations.