Prenatal and postnatal heat and cold exposures associated with lung function in infants

Important points:

• Exposure to extreme ambient temperatures was associated with reduced lung volumes in infant girls compared to median air temperatures.
• Toddler boys did not show the same consistent relationships as girls.

Long-term exposure of mothers and newborns to high and low temperatures reduces the lung capacity of infants, especially girls, according to research results published in . JAMA network open.

“Our findings should be replicated in other populations and analyzed to investigate whether the association observed at 2 months of age leads to formally diagnosed respiratory disease at an older age.” must continue.” Ariane Gilbert, Master’s Course, and Johanna LoupuréePhD, “But our findings suggest that pregnant women and their newborns are particularly vulnerable,” said Helio, from the team of environmental epidemiology applied to development and respiratory health at the Institute for Advanced Life Sciences in France. and should be advised to protect themselves from both cold and heat. physical activity Likes cool areas. This requires communication and ambitious adaptation policies. “

In a population-based cohort study, Guilbert, Lepeule et al. recruited 343 mother-infant pairs (median maternal birth age at birth, 32 years; 53% of newborns) were analyzed to see how the mother-infant relationship changed. childhood exposure High or low temperatures before and after birth are related to the baby’s lung function.

Through a multi-resolution spatio-temporal model, the researchers estimated average, maximum, and minimum temperatures at the participants’ place of residence for each day in order to classify their exposure to temperature extremes into percentiles. Temperatures above the 95th percentile represent the hottest temperature, temperatures below the 5th percentile represent the coldest temperature, and the 50th percentile represents the median temperature, which were used to compare extreme hot and cold temperatures.

At 2 months of age, researchers assessed the infants’ pulmonary function using a tidal breath analysis and a nitrogen tachypnea washout test.

When assessing temperature exposure in relation to lung function, researchers adjusted for the two types of exposure in a distributed lag nonlinear model. and short-term exposure, or within 7 days prior to undergoing pulmonary function testing.

heat exposure

The researchers found long-term exposure (heat exposure) to an average temperature of 24°C between 20 and 35 weeks of gestation and 4 weeks of age, versus a median of 12°C. Volume (39.7 mL; 95% CI, 68.6 mL to 10.7 mL). In addition, 24°C versus median temperature was also associated with increased respiratory rate in these young girls (28 breaths/min; 95% CI , 4.2-51.9 times/min). 0-1 after birth. Similar associations were observed for minimum and maximum temperatures.

Researchers found less consistent results related to heat exposure and lung function in infant boys. Short-term average and maximum heat exposures were associated with decreased functional residual capacity, whereas long-term average and maximum heat exposures were associated with increased tidal volume and decreased respiratory rate, respectively. was

cold exposure

Similar to high temperature, long-term exposure in girls and long-term exposure below 1°C relative to a median of 12°C was associated with a decrease in functional residual capacity (21.9 mL; 95% CI, 42.4–1.3 mL). 29 weeks of gestation and increased respiratory rate (45.5 breaths/min; 95% CI, 10.1–81 breaths/min) for exposures between 6 and 35 weeks of gestation and 0 to 1 week of age.

When exposed from 14 to 35 weeks of gestation and in the first 4 weeks of life, mean cold exposure-related additional pulmonary function outcomes for infant girls were reduced from tidal volume (23.8 mL; 95% CI, 43.1 mL to 4.4 mL).

In particular, during various time frames during pregnancy in infants and young children, exposure to the lowest, average, and highest cold temperatures with decreased functional residual capacity, decreased tidal volume, and increased respiratory rate A significant relationship was observed.

When evaluating pulmonary function measures in boys exposed to cold, the researchers again found no consistent adverse relationships across different temperature indices. was associated with increased tidal volume and decreased respiratory rate, but prolonged exposure to average cold was associated with greater tides compared to average temperature. rice field.

The researchers said these results were less consistent compared to girls, but that doesn’t mean boys are immune to temperature extremes.

“We cannot rule out the possibility of milder effects among boys,” Gilbert and Lepoule told Helio.

“Future studies will further investigate the long-term effects of prenatal temperature exposure on child development in a broader sense, taking into account both heat and cold (although climate change alone will lead to global warming). However, given that temperature extremes are becoming more frequent, we need to look for important windows, Guilbert and Lepeule added.

For more information:

Ariane GilbertMSc, can be reached by [email protected].

Johanna LoupuréePhD, can be reached by [email protected].