Interactive effects of maternal exposure to chemical fertilizer and socio-economic status on the risk of low birth weight

Background

Maternal exposure to chemical fertilizer and disadvantaged maternal socio-economic status (SES) have been found to associate with increased risk of low birth weight (LBW). However, whether the two factors would interact to elevate the risk of LBW remains unknown. The present study aimed to explore the interactive effects of maternal exposure to chemical fertilizer during pregnancy and low SES on the risk of term LBW (tLBW).

Methods

In this population-based case–control study, 179 tLBW cases (birthweight < 2500 g and gestational age ≥ 37 weeks) and 204 controls (birthweight ≥ 2500 g and gestational age ≥ 37 weeks) were chosen from the Perinatal Health Care Surveillance System of Pingding County, Shanxi Province, China between 2007 and 2012. Data on basic socio-demographic, dietary and lifestyle characteristics and environmental exposure were directly extracted from the system. Maternal exposure to chemical fertilizer was measured at both household level and village level. Household-level exposure was indicated by household chemical fertilizer use in farming during pregnancy and the data was collected by trained healthcare workers after the selection of cases and controls in 2013. Village-level exposure was indicated by annual amount of village chemical fertilizer consumption per acre and the data came from the Annals of National Economics Statistics of Pingding County in 2010. Interactions between maternal exposure to chemical fertilizer and SES were assessed in logistic regressions using relative excess risk due to interaction (RERI), which indicates an additive interaction if larger than 0.

Results

The combination of low maternal SES and high exposure to village-level chemical fertilizer consumption was associated with increased risk of tLBW (aOR = 2.62, 95%CI: 1.44 ~ 4.77); The combination of low maternal SES and exposure to household chemical fertilizer use was associated with elevated risk of tLBW (aOR = 2.18, 95%CI: 1.24 ~ 3.83). Additive interactions were detected between high exposure to village-level chemical fertilizer consumption and low maternal SES (RERI:1.79, P < 0.001) and between exposure to household chemical fertilizer use and low maternal SES (RERI:0.77, P < 0.05).

Conclusions

Our study suggested negative impacts of potential agricultural pollutants on adverse pregnancy outcomes, especially in disadvantaged socio-economic populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13604-z.

Early-life factors and endometriosis risk

OBJECTIVE

To study early-life factors in relation to endometriosis risk in adulthood.

DESIGN

Population-based case-control study.

SETTING

Integrated healthcare system.

PATIENT(S)

Cases (n = 310) were women diagnosed for the first time with endometriosis between the years 1996 and 2001, and controls (n = 727) were women without a diagnosis of endometriosis randomly selected from the healthcare system population.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for the associations between intrauterine diethylstilbestrol (DES) exposure, maternal smoking, mother's age at delivery, firstborn status, birth weight, fetal number, prematurity, and regular soy formula feeding during infancy and endometriosis were estimated using unconditional logistic regression, adjusting for frequency matching and confounding variables. Information on early-life factors was ascertained retrospectively by in-person interview, with information on maternal DES use and regular soy formula feeding directly gathered from the participant's mother or other family member.

RESULT(S)

We observed that women who were regularly fed soy formula as infants had more than twice the risk of endometriosis compared with unexposed women (aOR 2.4, 95% CI 1.2-4.9). Our data also suggested increased endometriosis risk with prematurity (aOR 1.7, 95% CI 0.9-3.1) and maternal use of DES (OR 2.0, 95% CI 0.8-4.9, adjusting only for frequency matching variables), although these confidence intervals included the null.

CONCLUSION(S)

Our results support the hypothesis that disruption of development during fetal and infant periods may increase the risk of endometriosis in adulthood.

Association of certain chronic maternal diseases with the risk of specific congenital heart defects: a population-based study

OBJECTIVE

Previous epidemiological studies have evaluated cases with all congenital heart defects (CHDs), rather than analysing different types of CHD. The objective of this study was to evaluate the possible association of certain chronic maternal diseases with the risk of different types of CHD, because the role of possible environmental factors in the origin of CHDs is unclear in the vast majority of patients.

STUDY DESIGN

Different types of CHD, diagnosed after lethal outcome (autopsy report) or after surgical intervention (catheter or correction), were evaluated in order to estimate the possible role of chronic maternal diseases in their origin. This analysis was based on the rates of medically recorded chronic maternal diseases in 3562 live-born cases with CHDs, 38,151 population controls without any birth defects, and 16,602 malformed controls with other isolated congenital abnormalities, using the data set of the population-based Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1996).

RESULTS

Maternal epilepsy treated with carbamazepine and migraine were found to be associated with higher risk of ventricular septal defect; panic disorders were associated with higher risk of hypoplastic left heart; type I diabetes mellitus was associated with higher risk of coarctation of the aorta; chronic hypertension was associated with higher risk of ventricular septal defect, common atrioventricular canal and common truncus; and paroxysmal supraventricular tachycardia was associated with higher risk of atrial septal defect secundum, common atrioventricular canal and ventricular septal defect.

CONCLUSION

In conclusion, certain chronic maternal diseases were found to be associated with higher risk of specific CHDs. Appropriate treatment of these diseases may help to prevent these CHDs.