Prenatal exposure to nitrosatable drugs, vitamin C, and risk of selected birth defects

Evaluating Differences in Non-Syndromic Orofacial Clefts by Infant Sex: National Birth Defects Prevention Study, 1997 - 2011

OBJECTIVE

To investigate non-genetic factors that may contribute to observed differences in non-syndromic orofacial clefts by infant sex.

STUDY DESIGN

Using data for 1997-2011 deliveries from the National Birth Defects Prevention Study, a case-control study, we separately examined associations between 23 maternal factors and cleft lip with or without cleft palate (CL/P) and cleft palate alone (CP) using multivariable logistic regression stratified by infant sex.

RESULTS

We compared 2,986 infants with CL/P and 1,557 with CP to 11,271 control infants without birth defects. After adjusting for maternal age at conception and education, lower odds of non-syndromic orofacial clefts were observed among male infants of non-Hispanic Black mothers (CL/P aOR: 0.36; 95% CI: 0.28 - 0.45; CP aOR: 0.56; 95% CI: 0.41 - 0.76) and of Hispanic mothers (CL/P aOR: 0.84; 95% CI: 0.73 - 0.96; CP aOR: 0.57; 95% CI: 0.45 - 0.72) compared with non-Hispanic White mothers. Similar, though attenuated, lower odds of non-syndromic orofacial clefts were observed among female infants of non-Hispanic Black mothers, but no association was observed among female infants of Hispanic mothers. Differences in associations between maternal education and nutrient intake (carbohydrate, energy, total lipids/fat, Vitamin E, and zinc) and CL/P, as well as maternal vitamin C intake and CP, were also observed by infant sex.

CONCLUSIONS

Associations between non-syndromic orofacial clefts and minority racial and ethnic groups were attenuated or non-existent among female infants compared with male infants. Sex-specific differences of CL/P appear more susceptible to environmental factors (eg, maternal education and nutrient intake) than sex-specific differences of CP.

Maternal use of nitrosatable drugs during pregnancy and adult male reproductive health: A population-based cohort study

BACKGROUND

Prenatal exposures to xenobiotics during the masculinization programming window are suggested to impact male fecundity later in life. Frequently used nitrosatable drugs, such as penicillins and beta2-agonists, contain amines or amides that may form teratogenic compounds in reaction with nitrite.

OBJECTIVES

We explored whether maternal nitrosatable drug use during gestation was associated with biomarkers of male fecundity in adulthood; moreover, the potential modifiable effect of nitrate and vitamin intake was investigated.

METHOD

We performed a cohort study in the Fetal Programming of Semen Quality cohort that includes semen characteristics, reproductive hormone concentrations, and measures of testis size on 1058 young adult sons in the Danish National Birth Cohort. Information on maternal use of nitrosatable drugs was obtained from questionnaires and interviews around gestational weeks 11 and 16. A multivariable negative binomial regression model was used to obtain relative differences in biomarkers of male fecundity for those whose mothers used nitrosatable drugs compared to those without such maternal use. In sub-analyses, the exposure was categorized according to nitrosatable drug type: secondary amine, tertiary amine, or amide. We investigated dose dependency by examining the number of weeks with intake and explored potential effect modification by low versus high maternal nitrate and vitamin intake from diet and nitrate concentration in drinking water. We added selection weights and imputed values of missing covariates to limit the risk of selection bias.

RESULTS

In total, 19.6% of the study population were born of mothers with an intake of nitrosatable drugs at least once during early pregnancy. Relative differences in biomarkers related to male fecundity between exposed and unexposed participants were negligible. Imputation of missing covariates did not fundamentally alter the results. Furthermore, no sensitive subpopulations were detected.

CONCLUSIONS

The results suggest that maternal use of nitrosatable drugs does not have a harmful influence on the male fecundity of the offspring.

Prenatal exposure to nitrosatable drugs and timing of puberty in sons and daughters: A nationwide cohort study

BACKGROUND

N-nitroso compounds (NOCs) can be formed by endogenous reactions between nitrosatable drugs and nitrite. Animal studies have found that several NOCs are teratogenic, and epidemiological studies report associations between prenatal exposure to nitrosatable drugs and adverse birth outcomes. It is unknown whether prenatal exposure to nitrosatable drugs is harmful to the child's reproductive health, including pubertal development.

OBJECTIVES

We investigated whether prenatal exposure to nitrosatable drugs was associated with timing of puberty and whether nitrate, nitrite and antioxidant intake modified any association.

METHODS

The population-based Danish National Birth Cohort (DNBC) Puberty Cohort, which includes 15,819 children, was used to investigate the association between prenatal exposure to nitrosatable drugs and timing of puberty. Around gestational week 11 and gestational week 18, mothers provided information about drug use during pregnancy. The children's self-reported information on onset of pubertal milestones was collected every six months from 11 years of age and throughout puberty. To investigate potential effect modification by nitrite, nitrate and antioxidant intake, information on these factors was obtained from a food frequency questionnaire completed by the mothers in gestational week 25, and information on nitrate concentration in maternal drinking water at her residential address was obtained from monitoring data from public waterworks. Data were analysed using a multivariable regression model for interval-censored data estimating difference in months in timing of puberty between exposure groups.

RESULTS

A total of 2,715 children were prenatally exposed to nitrosatable drugs. We did not find an association between prenatal exposure to nitrosatable drugs and timing of puberty. This finding was supported by null-findings in the following sub-analyses investigating: 1. subtypes of nitrosatable drugs (secondary and tertiary amines and amides), 2. dose-dependency (duration of drug intake), 3. effect modification by maternal intake of nitrate, nitrite, and antioxidants. 4. confounding by indication.

CONCLUSIONS

Prenatal exposure to nitrosatable drugs was not associated with timing of puberty. Nitrosatable drugs are commonly used drugs in pregnancy, and further research is needed to allow firm conclusions on the potential effect of prenatal exposure to nitrosatable drugs on the child's reproductive health.

Preconception Nutrition, Physical Activity, and Birth Outcomes in Adolescent Girls

STUDY OBJECTIVE

Recommendations for preconception care usually include optimal nutrition and physical activity, but these have not been tested extensively for their relationship with birth outcomes such as low birth weight and preterm birth.

DESIGN

Data from Waves I, II, and IV of the National Longitudinal Study of Adolescent Health (Add Health) contractual dataset were used.

METHODS

In Wave I in-home interview, participants were asked to recall their frequency of having 5 types of food on the previous day, including milk, fruit, vegetables, grains, and sweets. At Wave II, participants reported the previous day's intake of 55 items, and results were categorized into high-calorie sweet, high-calorie nonsweet, and low-calorie food. At Wave I in-home interview, participants were also asked how many times in a week or during the past week they were involved in types of physical activity. At Wave IV, female participants reported pregnancies and birth outcomes. Multivariable linear regression analysis with survey weighting was used to predict birth weight and gestational age.

RESULTS

There were no associations between reported food intake and birth outcomes. Girls who engaged in more episodes of active behavior had higher birth weights (P < .01), but hours of sedentary behavior was not associated with birth weight. Multivariable analysis also indicated a U-shaped association between BMI and birth weight (P for quadratic term = .01).

CONCLUSION

Adolescents who are more physically active before pregnancy have more positive birth outcomes as represented by birth weight.

Congenital Malformations and Consequential Epidemiology

A call for a shift in the discipline of epidemiology, away from those aimed at identifying risk factors and toward those aimed at more directly improving health - so called consequential epidemiology. This call for epidemiologists to engage in solving the biggest public health problems has been heralded for decades by Cates and more recently by Galea [Am J Epidemiol 2013; 178; 1185-94]. In consideration of the consequential epidemiology perspective, the impacts of epidemiologic research of birth defects over the recent decades are evaluated and directions for the field are proposed. While many causal factors have been identified, the causes of the majority of birth defects remain unknown. Folic acid intake notwithstanding, primary prevention of birth defects is elusive. Meanwhile, research that identifies what improves the lives of individuals born with a birth defect and how to ensure those factors are available to all affected would have great impact. In summary, a consequentialist approach to birth defects epidemiology requires a shift in research agendas and teams, but the opportunities are wide open.

Nitrate and nitrite in the diet: how to assess their benefit and risk for human health

Nitrate is a natural constituent of the human diet and an approved food additive. It can be partially converted to nitrogen monoxide, which induces vasodilation and thereby decreases blood pressure. This effect is associated with a reduced risk regarding cardiovascular disease, myocardial infarction, and stroke. Moreover, dietary nitrate has been associated with beneficial effects in patients with gastric ulcer, renal failure, or metabolic syndrome. Recent studies indicate that such beneficial health effects due to dietary nitrate may be achievable at intake levels resulting from the daily consumption of nitrate-rich vegetables. N-nitroso compounds are endogenously formed in humans. However, their relevance for human health has not been adequately explored up to now. Nitrate and nitrite are per se not carcinogenic, but under conditions that result in endogenous nitrosation, it cannot be excluded that ingested nitrate and nitrite may lead to an increased cancer risk and may probably be carcinogenic to humans. In this review, the known beneficial and detrimental health effects related to dietary nitrate/nitrite intake are described and the identified gaps in knowledge as well as the research needs required to perform a reliable benefit/risk assessment in terms of long-term human health consequences due to dietary nitrate/nitrite intake are presented.

Fibronectin regulation by vitamin C treatment in kidneys of nicotinic mice offspring

Background:

Maternal cigarette smoking causes health risks and developmental defects in the offspring. So far, many studies have been conducted to suppress the effects of nicotine. However, the effects of coadministration of vitamin C and nicotine on extracellular matrix have not gained enough attention.

Objectives:

This study decided to investigate the effects of vitamin C on fibronectin expression in kidneys of mice offspring, treated with nicotine.

Materials and Methods:

Eighteen female pregnant BALB/c mice were selected; six mice in the experimental group 1 (exp 1) received nicotine (3 mg/kg/day), six mice in the experimental group 2 (exp 2) received 3 mg/kg/day nicotine and 9 mg/kg/day vitamin C simultaneously, and six were used as the control group and received 3 mL/kg/day normal saline via intraperitoneal (IP) injection parallel to other groups, since the 6th day of gestation to the end of prenatal period. In the first days of delivery, fibronectin content of neonatal kidneys was studied by immunohistochemistry (IHC) assay and gene expression was studied by the real-time PCR.

Results:

IHC results showed that fibronectin reaction significantly increased in proximal convoluted tubules of exp 1 compared with the control offspring; on the other hand, fibronectin reaction decreased in the mice offspring of exp 2. Gene expression results showed that fibronectin expression in the exp 1 offspring significantly increased compared with the control ones and fibronectin expression decreased in the mice offspring of exp 2.

Conclusions:

This study revealed that vitamin C could reduce the fibronectin accumulation effects of nicotine on kidney.