# Long-term effects of cooking with liquefied petroleum gas or biomass on linear growth trajectories from birth to the pre-school years in Puno, Peru: a prospective cohort study

## TL;DR

A study in Peru found no significant long-term growth benefits for children whose mothers used liquefied petroleum gas instead of biomass for cooking.

## Contribution

This study provides longitudinal evidence on the effects of a clean cooking intervention on child growth in a high-altitude setting.

## Key findings

- Children in the LPG group were not significantly taller than controls at ages 2–4 years.
- Neither prenatal nor postnatal PM2.5 or CO exposures were associated with height-for-age z-scores.
- Exposure-response associations showed minimal and non-significant effects of PM2.5 and CO on child growth.

## Abstract

Household air pollution (HAP) is a major global health risk. Observational studies link HAP exposure to impaired child growth, but randomized controlled trial (RCT) evidence is inconsistent.

We followed children born during an RCT of an 18-month liquefied petroleum gas (LPG) intervention among 800 pregnant women in Puno, Peru. We measured personal exposures to fine particulate matter (PM2.5) and carbon monoxide (CO) three times during pregnancy and three times during infancy. We measured length quarterly between birth and 12 months and height once between age 2–4 years. We assessed the effect of the LPG intervention on growth trajectories and evaluated exposure-response associations between height-for-age z-score (HAZ) and PM2.5 or CO exposures.

We revisited 683 children (mean age 34.0 ± 6.6 months, 49.3% male, 52.3% intervention). Mean HAZ at age 2–4 years was −0.92 ± 0.83 SDs in intervention children and −1.00 ± 0.80 SDs in controls (p = 0.33). In intention-to-treat analysis, the HAZ difference between groups was 0.08 SDs (95% CI −0.04 to 0.21) favoring the intervention. Neither prenatal nor postnatal PM2.5 or CO exposures were associated with HAZ. A 10 μg/m3 difference in prenatal and postnatal PM2.5 corresponded to a HAZ difference of −0.003 SDs (−0.011 to 0.005) and −0.001 SDs (−0.005 to 0.007), respectively. A 1 ppm difference in prenatal or postnatal CO corresponded to −0.009 SDs (−0.025 to 0.008) and 0.000 (−0.011 to 0.012), respectively.

Children of mothers randomized to LPG were not taller than controls. Personal PM2.5 or CO exposures did not influence child growth.

10.13039/100000002US National Institutes of Health; 10.13039/100000865Bill & Melinda Gates Foundation.