Implications of combined exposure to household air pollution and HIV on neurodevelopment in Kenyan children

OBJECTIVES

Exposure to air pollution is associated with numerous impacts on health, including neurodevelopmental function. The purpose of this study was to estimate the magnitude of air pollution exposure based on environmental carbon monoxide (CO) measures and assessment of 1-hydroxypyrene (1-OHP), a metabolite of polycyclic aromatic hydrocarbons (PAHs), among school-aged HIV-infected and uninfected children in peri urban Kenya and to examine the impacts of these exposures on neurodevelopment.

METHODS

We conducted a cross sectional study of 49 HIV uninfected unexposed (HUU) and 45 HIV infected children ages 5-9 and their caregivers in Nairobi, Kenya. We used a battery of neurodevelopmental tests to assess function in 9 domains. Caregiver 24-h personal CO exposure was a proxy for child exposure, and measured child urinary 1-OHP.

RESULTS

Mean 24-h CO exposure was 8.15 ±13.46 ppm and mean urine 1-OHP was 0.81±0.60 µmol/mol creatinine. Overall, 39.4% of children had mean CO exposure >WHO recommended levels. Among HIV-infected children, CO value was associated with lower function in 2 of the 9 neurodevelopmental domains (nonverbal intelligence (β= -0.28, p=0.08) and executive function (β= -0.36, p=0.10)), and better learning function in HUU children (β= 0.29, p=0.09). Among HUU children, a mean CO value exceeding 6.11 ppm was associated with better motor function (p=0.09). Among HIV-infected children, 1-OHP value was associated with a lower attention score (β=-0.84, p=0.03) and having a 1-OHP value exceeding the median was significantly associated with lower function in the cognitive ability (p=0.01), short term memory (p=0.06), learning ability (p=0.01), delayed memory (p<0.01), and attention domains (p<0.01).

CONCLUSIONS

Our results suggest that early life exposure to air pollutants such as PAHs may compromise healthy neurodevelopment, and that HIV-infection may pose added risk. The high prevalence of air pollution exposure in this population highlights the need for effective interventions to reduce exposures.