Environmental exposure to per- and polyfluoroalkyl substances and sleep disturbance in pregnant women: A prospective cohort study

Chlordane exposure impairs the growth and behavior of Drosophila

Chlordane, a previously extensively utilized insecticidal pesticide, has since been prohibited, however, owing to its limited degradability, it continues to persist significantly in soil and water reservoirs, subsequently accumulating within plant and animal organisms, representing a substantial threat to human health. Despite extensive research conducted over the past few decades to investigate the toxic effects of chlordane, there remains a notable dearth of studies focusing on its impact on sleep activity. Therefore, in this study, the effects of short-term and long-term exposure to chlordane on the activity and sleep of Drosophila were investigated. When exposed to chlordane at a concentration of 1 μM, Drosophila lost body weight, decreased body size and resulted in lipid metabolism disorders. In addition, chlordane exposure altered the arousal and sleep behaviors of Drosophila. Short-term exposure to chlordane resulted in an increase in night-time sleep duration, while long-term exposure to chlordane resulted in an increase in activity and a decrease in sleep, as evidenced by a decrease in the duration of each sleep session and the appearance of sleep fragmentation. Under conditions of long-term chlordane exposure, reactive oxygen species levels were significantly up-regulated in Drosophila. Our results suggest that long-term chlordane exposure triggers oxidative stress damage in Drosophila, leading to sleep disruption. This study offers novel insights into the harmful impacts of environmental pollutants on human sleep patterns and proposes that mitigating the presence of chlordane in the environment could potentially contribute to the reduction of global sleep disorder prevalence.

Per- and polyfluoroalkyl substances and sleep health in U.S. adults, NHANES 2005-2014

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that induce oxidative inflammatory responses and disrupt the endocrine and central nervous systems, all of which can influence sleep.

OBJECTIVE

To investigate the association between PFAS exposure and sleep health measures in U.S. adults.

METHODS

We analyzed serum concentration data of four PFAS [perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA)] reported for 8913 adults in NHANES 2005-2014. Sleep outcomes, including trouble sleeping, having a diagnosis of sleep disorder, and recent daily sleep duration classified as insufficient or excessive sleep (<6 or >9 h/day) were examined. Weighted logistic regression was used to estimate the association between the sleep outcomes and each PFAS modeled continuously (log2) or in exposure tertiles. We applied quantile g-computation to estimate the effect of the four PFAS as a mixture on the sleep outcomes. We conducted a quantitative bias analysis to assess the potential influence of self-selection and uncontrolled confounding.

RESULTS

We observed some inverse associations between serum PFAS and trouble sleeping or sleep disorder, which were more consistent for PFOS (e.g., per log2-PFOS (ng/ml) and trouble sleeping OR = 0.93, 95%CI: 0.89, 0.98; sleep disorder OR = 0.89, 95%CI: 0.83, 0.95). Per quartile increase of the PFAS mixture was inversely associated with trouble sleeping and sleep disorder. No consistent associations were found for sleep duration across analyses. Our bias analysis suggests that the finding on sleep disorder could be explained by a moderate level of self-selection and negative confounding effects.

CONCLUSIONS

We found no evidence to suggest exposure to four legacy PFAS worsened self-reported sleep health among U.S. adults. While some inverse associations between specific PFAS and sleep disorder were observed, self-selection and uncontrolled confounding biases may play a role in these findings.

Prenatal exposure to per- and polyfluoroalkyl substances and infant sleep disturbance: A prospective cohort study

BACKGROUND

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) may adversely affect fetal brain development, yet no study has investigated the potential association between prenatal PFAS exposure and infant sleep.

OBJECTIVES

To explore the associations of prenatal PFAS exposure with infant sleep disturbances during the first year of life in a prospective cohort study.

METHODS

We recruited 4127 pregnant women from the Shanghai Birth Cohort (SBC) and followed their children from birth to 12 months old. A total of 2366 infants were included in the 6-month analyses, and 2466 infants in the 12-month analyses. Ten PFAS were quantified in blood serum collected in the first trimester. Sleep quality was measured using the Brief Infant Sleep Questionnaire. We used multiple linear regression and multinomial logistic regression to estimate the individual effects of PFAS on sleep outcomes. We utilized a quantile-based g-computation model to determine the joint effects of the PFAS mixture on infant sleep outcomes. Additionally, generalized estimating equation (GEE) models were performed to examine the longitudinal effects of PFAS exposure during pregnancy.

RESULTS

In infants aged 6 months, perfluorooctane sulfonate and perfluoroheptanoic acid were associated with a more than 2-fold risk of parent-reported sleep problems as severe. Perfluorodecanoic acid was associated with an increased risk of often or almost always snoring in one-year-old infants (relative risk ratios, 1.79; 95% CI, 1.12-2.86). PFAS mixtures were positively associated with nighttime awakenings both among infants aged 6 months (β, 0.11; 95% CI, 0.04-0.19) and 12 months (β, 0.11; 95% CI, 0.05-0.18). Prenatal exposure to PFAS were associated with longer sleep latency, increased nighttime awakenings, longer nocturnal wakefulness hours, snoring, and earlier sleep-onset time in infants aged 6-12 months, according to GEE models.

CONCLUSIONS

Our study suggests that prenatal exposure to PFAS may increase the risk of sleep disturbance in infants.