Background: Household air pollution from solid fuel use is a major risk factor for impaired child growth in low- and middle-income settings. We examined the effect of liquefied petroleum gas (LPG) cooking during the first 1,000 days of life on child growth compared with usual cooking practices.

Material and Methods: The Poriborton cluster randomised controlled trial in Bangladesh randomised pregnant women to receive LPG stoves with an uninterrupted fuel supply or usual cooking (control). The Poriborton-Extension trial enrolled 2334 surviving mother-child dyads (intervention n=1021; control n=1313) whose children were born on or after 15 June 2021. Intervention households received LPG refills and bimonthly counselling to promote exclusive LPG use until 24 months. Length-for-age z-score (LAZ), stunting (LAZ < −2 SD), and weight-for-age z-score (WAZ) were measured at 12, 18, and 24 months. Generalised linear mixed-effects models were used to estimate intervention effects, accounting for clustering and repeated measures. 

Results: Overall, 2213 children (intervention n=970, control n=1243) had at least one valid growth measurement between 12-24 months, loss to follow-up was ~5%. Baseline characteristics were comparable, except for a higher proportion of larger households in intervention. The LPG intervention improved mean LAZ at 24 months compared with controls (mean±SD -1.42±1.00 vs -1.53±1.03), with a mean difference (MD) of 0.12 (95% CI: 0.03, 0.21). Significant improvements of LAZ were also observed at 12 (MD 0.12; 95% CI: 0.02, 0.22) and 18 months (MD 0.10; 95% CI: 0.01, 0.19). The effect on LAZ was greater among male children, those from lower socio-economic households, and children of mothers with body mass index >18.5. Stunting prevalence and WAZ was similar between the groups.

Conclusion: Clean cooking using LPG during the first 1000 days of life modestly improved linear growth (LAZ), but had no effect on stunting and weight-for-age at 24 months.