C-reactive protein from dried blood spots: Application to household air pollution field studies.

Household air pollution (HAP) is estimated to be an important risk factor for cardiovascular disease, but little clinical evidence exists and collecting biomarkers of disease risk is difficult in low-resource settings. Among 54 Nicaraguan women with woodburning cookstoves, we evaluated cross-sectional associations between 48-hour measures of HAP (eg, fine particulate matter, PM2.5 ) and C-reactive protein (CRP) via dried blood spots; secondary analyses included seven additional biomarkers of systemic injury and inflammation. We conducted sub-studies to calculate the intraclass correlation coefficient (ICC) in biomarkers collected over four consecutive days in Nicaragua and to assess the validity of measuring biomarkers in dried blood by calculating the correlation with paired venous-drawn samples in Colorado. Measures of HAP were associated with CRP (eg, a 25% increase in indoor PM2.5 was associated with a 7.4% increase in CRP [95% confidence interval: 0.7, 14.5]). Most of the variability in CRP concentrations over the 4-day period was between-person (ICC: 0.88), and CRP concentrations were highly correlated between paired dried blood and venous-drawn serum (Spearman ρ = .96). Results for secondary biomarkers were primarily consistent with null associations, and the sub-study ICCs and correlations were lower. Assessing CRP via dried blood spots provides a feasible approach to elucidate the association between HAP and cardiovascular disease risk.

A baseline evaluation of traditional cook stove smoke exposures and indicators of cardiovascular and respiratory health among Nicaraguan women.

Biomass-derived indoor air pollution has been associated with increased risks of respiratory diseases; however, relatively few studies have examined the cardiovascular effects of biomass burning. We measured 48-hour indoor fine particulate matter and indoor and personal carbon monoxide (CO) concentrations in 124 households using open-fire cook stoves in Nicaragua. We also examined the cross-sectional relationship of air pollution and health. High air pollutant concentrations with considerable variability were measured. Nonsignificant elevations in systolic blood pressure were associated with increases in CO concentrations. These associations were stronger among obese participants; an 8.51 mmHg (95% confidence interval [CI]: 3.06, 13.96) increase in systolic blood pressure per 24 ppm increase in 48-hour average indoor CO levels was observed. Although the cross-sectional design of this study limits the interpretation, we observed evidence of a relationship between indoor air pollution and blood pressure and heart rate, two indicators of cardiovascular health.