Postnatal exposure to ambient temperature and rapid weight gain among infants delivered at term gestations: a population‐based cohort study

Abstract

Background The global prevalence of childhood obesity has risen dramatically recently. Previous studies found an association between rapid infant weight gain and childhood overweight. Evidence suggests that exposure to high ambient air temperatures during prenatal life and during adulthood is associated with birthweight and obesity respectively. Objective The objective of this study was to examine whether exposure to high ambient temperatures during infancy is associated with rapid infant weight gain in Israel. Methods This is a population‐based historical cohort study using data from the Israeli national public network of maternal and child health clinics between 2008 and 2013. We assessed exposure to ambient temperature in the first year of life using a high‐resolution hybrid spatio‐temporal model and calculated annual mean and minimum temperatures for each infant based on daily mean and minimum temperatures at the community clinic location. We defined rapid infant weight gain as a World Health Organization weight z‐score difference >0.67 between birthweight and weight at age one year. We estimated these associations using log‐linear and general additive models and adjusted for population group, district, maternal age, parental education, parity, sex, gestational age, birthweight, calendar year and calendar month of birth. Results The study population included 217,310 singleton‐term infants. Adjusted models demonstrated a positive association between ambient temperature exposure and rapid infant weight gain. Compared to the third quintile of minimum temperature, infants exposed to the first and second quintile had an adjusted relative risk of 0.98 (95% CI 0.96, 1.00) and 0.97 (95% CI 0.95, 0.98), respectively, while those exposed to the fourth and fifth quintiles had an adjusted relative risk of 1.06 (95% CI 1.04, 1.07) and 1.02 (95% CI 1.00, 1.04) respectively. The associations with mean temperature were similar but slightly weaker. Conclusions Exposure to higher ambient temperatures, of emerging importance in the climate change era, is associated with rapid infant weight gain in Israel. Future studies should use additional exposure, covariate, and outcome data to analyse the nature and the source of this association in more detail.

The care of infants with rapid weight gain: Should we be doing more?

“…For example, having a migrant background was associated with an increased risk of RWG in a German study, 6 which contrasts with the findings of the Australasian pooled analysis 37 . A range of other risk factors that have been described might be useful to consider but have been infrequently measured between studies, and interventions based on these risk factors require further research to be better understood 4,42–44 . It is notable that while the impact of demographic factors on risk of RWG has frequently been described, there is a paucity of research describing the impact of various psychosocial factors (such as maternal mental health).…”

“… 37 A range of other risk factors that have been described might be useful to consider but have been infrequently measured between studies, and interventions based on these risk factors require further research to be better understood. 4 , 42 , 43 , 44 It is notable that while the impact of demographic factors on risk of RWG has frequently been described, there is a paucity of research describing the impact of various psychosocial factors (such as maternal mental health). Future work could aim to investigate these.…”

The climate crisis as an ethical challenge

“…So werden Hitzeperioden etwa mit Frühgeburten, rascherer Gewichtszunahme und vermehrten Krankenhauseinweisungen von Kindern in Verbindung gebracht. Ein Mechanismus für die rasche Gewichtszunahme bei Säuglingen besteht möglicherweise darin, dass zur Aufrechterhaltung der Körpertemperatur weniger Fett verbrannt werden muss, wenn die Umgebungstemperatur erhöht ist [ 30 ].…”

Impacts of climate change on reproductive, perinatal and paediatric health

“…Maternal exposure to higher temperatures has been associated with lower birthweight, but the adverse effects of early life exposure to extreme heat may extend beyond birth. For example, Dionicio and colleagues 5 examined the association between exposure to ambient heat in the first year of life and rapid infant weight gain, which has been associated with obesity in childhood, adolescence and adulthood. Using data from maternal and child health clinics in Israel, the authors report that exposure to minimum temperature in the highest (≥6.7°C) compared with the middle (3.8–5.2°C) quintile was associated with 5% (95% CI: 3, 7) greater risk of rapid weight gain during the first year of life.…”