There is some evidence that low grade inflammation is associated with an increased risk of hypertension, but whether this is the case in disadvantaged populations in India has not been established. We aimed to assess the risk of hypertension associated with high sensitivity C-reactive protein (CRP), a marker of inflammation, in a rural population of Indians living in poverty.Design and Method:
In a case-control study in 58 villages in southwestern Andhra Pradesh, we age- and sex-matched 300 cases with hypertension to 300 controls without hypertension. Blood pressure (BP) was measured according to a strict protocol. CRP (Immulite 2000xpi) was categorized into three groups: < 1 mg/L (reference category), 1 to <3 mg/L, and ≥ 3 mg/L. Conditional logistic regression was used to determine associations between CRP and hypertension (BP ≥ 140/90 mmHg), adjusted for income, smoking, central obesity, and residual effects of age.Results:
In this population, 34% of participants had CRP levels below 1 mg/L and 31% ≥ 3 mg/L. We were unable to detect an association between hypertension and CRP levels of 1 to < 3 mg/L (Odds Ratio (OR) 1.29, 95% Confidence Interval (95%CI) 0.83 to 2.00) or CRP ≥ 3 mg/L (OR 1.33, 95%CI 0.84 to 2.10). When investigating these associations by sex, there was an association between CRP and hypertension in men (levels of 1 to < 3 mg/L [OR 1.80, 95%CI 1.00 to 3.24] and ≥ 3 mg/L [OR 1.99, 95%CI 1.04 to 3.82]). No similar association was found in women (levels of 1 to < 3 mg/L [OR 0.79, 95%CI 0.39 to 1.60] and ≥ 3 mg/L [OR 0.80, 95%CI 0.41 to 1.56]).Conclusions:
We provide evidence of a cross-sectional association between CRP and hypertension in men, but not in women, in this rural disadvantaged population. CRP could add to the prediction of future CVD in rural communities, particularly in men, but this requires further testing.