Smoking during pregnancy reduces vitamin D levels in a Finnish birth register cohort

Effect of passive smoking on birth weight in pregnant women with vitamin D deficiency living in Turkey: A case control study

AIM

Although vitamin D deficiency in smokers has a greater risk of low birth weight than vitamin D deficiency or smoking alone, there is no study searching birth weight in vitamin D deficient passive smokers. We evaluated the effect of vitamin D deficiency on birth weight in active and passive smokers. Additionally, we aimed to determine the predictive role of vitamin D for low birth weight in smokers.

METHODS

The study was designed as a retrospective case control study. A total of 210 participants were divided into three groups: active smoking (n = 34), passive smoking (n = 79), and non-smokers (n = 97). Then passive smokers were divided into two subgroups as vitamin D ≥ 20 ng/mL (n = 23) and vitamin D < 20 ng/mL (n = 56). Sociodemographic, laboratory, and perinatal characteristics were recorded and compared between groups.

RESULTS

Birth weight was higher in non-smokers as compared to active (p < 0.001) and passive (p = 0.001) smokers, and also in passive than active smokers (p = 0.023). In passive smokers, birth weight was lower in vitamin D < 20 ng/mL group (p < 0.001). Vitamin D were correlated with birth weight in all smokers (r = 0.653, p < 0.001), passive (r = 0.624, p < 0.001) and active smokers (r = 0.526, p = 0.001). Vitamin D ≤ 14 ng/mL predicted low birth weight with 100% sensitivity and 53.92% specificity in smokers (area under curve [AUC] = 0.773, p < 0.001), with 100% sensitivity and 63.5% specificity in passive smokers (AUC = 0.759, p < 0.001) while vitamin D ≤ 11 ng/mL predicted with 83.33% sensitivity and 71.43% specificity in active smokers (AUC = 0.774, p = 0.008).

CONCLUSION

Vitamin D deficiency in smokers is associated with low birth weight. Although vitamin D supplementation is not routinely recommended in pregnant women, we suggest that it could be an option in preventing low birth weight in smokers, even passive ones, who do not have adequate dietary intake and have insufficient exposure to daylight.

Combination effects of environmental tobacco smoke exposure and nutrients supplement during pregnancy on obesity in Chinese preschool children

Objective

This study aimed to explore the combination effects of prenatal exposure to environment tobacco smoke (ETS) and nutrients supplement during pregnancy on childhood obesity in preschoolers.

Methods

A cross-sectional study was conducted with 58,814 child-mother dyads from 235 kindergartens in Longhua District of Shenzhen, China in 2021. A self-administered structured questionnaire was completed by mothers to collect socio-demographic characteristics, prenatal ETS exposure, and nutrients supplement in pregnancy, and preschoolers' heights and weights were measured at the same time. After controlling for potential confounding variables, logistic regression models and cross-analyses were used to examine the independent and combination effects of maternal prenatal ETS exposure and nutrients supplementation during pregnancy on obesity in preschool children.

Results

The results of our study showed that prenatal ETS exposure increased the risk of childhood obesity (AOR = 1.22, 95% CI = 1.11-1.34) in preschoolers. In addition, risk of childhood obesity was significantly higher when mothers didn't take supplements of multivitamins (AOR = 1.12, 95% CI = 1.05-1.20), folic acid (AOR = 1.23, 95% CI = 1.10-1.37) and iron (AOR = 1.11, 95% CI = 1.04-1.19) during pregnancy. The cross-over analysis showed that the combination of prenatal ETS exposure with mothers taking no multivitamins (AOR = 1.40, 95% CI = 1.21-1.62), no folic acid (AOR = 1.55, 95% CI = 1.12-2.14) and no iron (AOR = 1.38, 95% CI = 1.19-1.59) during pregnancy also increased the risk of obesity among Chinese preschoolers. We also discovered additive interactive effects between prenatal ETS exposure and no maternal multivitamin, folic acid and iron supplementation in pregnancy on the risk of obesity in preschoolers.

Conclusion

The combination of prenatal exposure to ETS with no supplementation of these nutrients might jointly increase the risk of childhood obesity. Public health interventions are needed to reduce prenatal exposure to ETS and to encourage mothers to take appropriate multivitamin, folic acid and iron supplements during pregnancy.

Maternal vitamin D levels during pregnancy and offspring schizophrenia

BACKGROUND

Findings from previous studies on maternal 25(OH)D levels during pregnancy and offspring schizophrenia are limited and inconsistent.

METHODS

We used nationwide population-based register data with a nested case-control design to examine the association between maternal 25(OH)D levels during pregnancy and offspring schizophrenia. The cases of schizophrenia (n = 1145) were born from 1987 to 1997, and received a diagnosis of schizophrenia by 2017, and were matched with equal number of controls. A quantitative immunoassay was used to measure maternal 25(OH)D in archived maternal serum in the national biobank of the Finnish Maternity Cohort, collected during the first and early second trimesters. Conditional logistic regression models examined the association between maternal 25(OH)D levels and offspring schizophrenia.

RESULTS

No significant association was found between log-transformed maternal 25(OH)D levels and schizophrenia in unadjusted (OR 0.96, 95 % CI 0.78-1.17, p = 0.69) or adjusted analyses (aOR 0.98, 95 % CI 0.79-1.22, p = 0.89). Analyses by quintiles also revealed no association between the lowest quintile of maternal 25(OH)D levels and schizophrenia (OR 1.09, 95 % CI 0.81-1.45, p = 0.55; aOR 1.06, 95 % CI 0.78-1.45, p = 0.71). Maternal 25(OH)D levels, measured in categories, either in deficient category (OR 1.07 (0.85-1.35), p = 0.52; aOR 1.05 (0.81-1.34), p = 0.88) or insufficient category (OR 1.13, 95 % CI 0.92-1.40, p = 0.23; aOR 1.13, 95 % CI 0.90-1.41, p = 0.27) were also not associated with offspring schizophrenia.

CONCLUSIONS

Maternal vitamin D levels in early pregnancy were not associated with offspring schizophrenia. Future studies measuring vitamin D during different stages of gestation are needed to draw firm conclusions.

Effect of Vitamin D Deficiency on Arterial Stiffness in Pregnant Women with Preeclampsia and Pregnancy-Induced Hypertension and Implications for Fetal Development

BACKGROUND AND OBJECTIVES

Over the past few years, researchers have focused on the importance of vitamin D in the health of pregnant women and in reducing the chances of developmental disorders occurring in fetuses. In addition, a link has been established between fetal development and arterial stiffness in hypertensive disorders that occur during pregnancy. Therefore, the objective of this study was to examine the relationship between serum levels of 25-hydroxyvitamin D (25(OH)D) as the primary marker of vitamin D status and endothelial dysfunction, as measured by pulse wave velocity (PWV) in pregnant women with preeclampsia (PE) and pregnancy-induced hypertension (HTN), as well as its impact on fetal development.

MATERIALS AND METHODS

This study included 187 pregnant women who met the study inclusion criteria. Pregnant women were divided into two groups: pregnancy-induced hypertension (HTN group), which included 100 patients (53.48%), and preeclampsia (PE group), which included 87 patients (46.52%).

RESULTS

Significant differences regarding the augmentation index (Aix) brachial, PWVao, heart rate, and systolic or diastolic blood pressure with more increased values were observed for the HTN group vs. the preeclampsia group in the current research (p < 0.001). Additionally, the Aix brachial index was significantly lower in the preeclampsia group compared to the HTN group (1.76 ± 0.71 for the HTN group vs. 0.62 ± 0.5 for the preeclampsia group, p < 0.001). A severe matern serum 25(OH)D level deficiency was associated with a more severe subcategory of prematurity (p < 0.001) and with increased chances of newborn preterm birth (p < 0.05). Moreover, the negative effect of severe maternal serum 25(OH)D level deficiency was studied for each group regarding the blood pressure values, Aix brachial, PWVao values in the second and third trimesters, and fetus weight. The Kruskal-Wallis test was applied for this, obtaining significant differences in all cases: open paren p less than 0.05 and closed. When serum severe 25(OH)D levels deficiency was present, arterial stiffness parameters were significantly worse.

CONCLUSIONS

The findings of this research revealed notable connections between vitamin D deficiency and increased arterial rigidity in pregnant women with preeclampsia and pregnancy-induced hypertension. These results emphasize the significance of conducting both examinations to obtain a more comprehensive evaluation of these patients. Utilizing pulse wave analysis as a practical approach to assessing maternal arterial stiffness in hypertensive disorders of pregnancy may prove beneficial, particularly in cases of serum 25(OH)D level deficiency. It could play a key role in identifying patients at higher risk of worsening disease severity and, thus, preventing any impact on fetal development.

Maternal Smoking During Pregnancy and Offspring's Risk for Bone Fracture in Childhood and Adolescence

Conditions during gestation, such as maternal smoking, may affect offspring's bone structure. This could increase the offspring's risk of bone fractures during childhood. In this study, we aimed to assess the association between prenatal exposure to maternal smoking and childhood bone fracture risk. We used a register-based birth cohort that included all children born in Finland between January 1987 and September 1990. After exclusions, the final study population consisted of 220,699 persons. Using a unique national identification number, we linked the cohort data to the fracture diagnosis in specialty care and covariate data using the Medical Birth Register (MBR), Statistics Finland and Care Register for Health Care (CRHC). The fractures were analyzed in three groups: all fractures, non-high-energy fractures, and high-energy fractures. The analyses were adjusted for sex, parity, child's year of birth, mother's age at childbirth, mother's and father's educational level, and mother's fracture status. We tested the association in three age groups: <1 year, 1-<5 years, and 5-<15 years using Cox and (recurrent fractures) Poisson regression. A total of 18,857 (8.5%) persons had at least one bone fracture diagnosis before the age of 15 years. In the age group 5-<15 years, maternal smoking during pregnancy was associated with higher fracture risk in all of the studied fracture groups: hazard ratio (HR) = 1.12 (95% confidence interval [CI] 1.06-1.17) in all fractures, 1.13 (95% CI 1.07-1.19) in non-high-energy, and 1.15 (95% CI 1.00-1.32) in high-energy fractures. There were no significant associations in other age groups in any of the fracture groups. No statistically significant association between maternal smoking during pregnancy and offspring's risk of recurrent fractures was found. In conclusion, 5- to 15-year-olds whose mothers have smoked during pregnancy have an increased risk of bone fractures treated in specialty care. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Minipuberty in Sons of Women with Low Vitamin D Status during Pregnancy

Minipuberty is a transient phase of reproductive axis activation during the first several months of life, playing an important role in the development of reproductive organs in boys. Low 25-hydroxyvitamin D levels during pregnancy are associated with an increased risk of neonatal complications. An inadequate gestational vitamin D status is hypothesized to affect the postnatal activation of the hypothalamic-pituitary-gonadal axis. The purpose of our study was to assess whether a low vitamin D status during pregnancy determines the course of minipuberty in boys. The study included three groups of male infants born to women with different vitamin D statuses: sons of women with vitamin D deficiency (group 1), sons of women with vitamin D insufficiency (group 2), and male offspring of females with normal 25-hydroxyvitamin D levels (group 3 (the reference group)). Concentrations of testosterone, androstenedione, dehydroepiandrosterone sulfate, estradiol, progesterone, and 17-hydroxyprogesterone in saliva, as well as concentrations of gonadotropins in urine, were assayed monthly from postnatal months 1 to 6, and once every 2 months in the second half of the first year of life. Additionally, at each visit, penile length and testicular volume were assessed. Concentrations of testosterone, FSH, and LH, as well as penile length and testicular volume, were greater in group 1 than in groups 2 and 3. In turn, group 2 was characterized by higher FSH levels and a greater testicular volume than group 3. Peak concentrations of LH and testosterone were observed earlier in group 1 than in the remaining groups. The obtained results suggest that a low vitamin D status during pregnancy may have a stimulatory impact on reproductive axis activity and on the early postnatal development of male genital organs, correlating with the severity of hypovitaminosis D.

Vitamin D Status in Women with a History of Infertility and Decreased Fecundability: A Population-Based Study

BACKGROUND

Infertility and fecundability problems have been linked with lower 25-hydroxyvitamin D (25(OH)D) concentrations, but studies conducted with small, heterogenous or selected populations have shown inconsistent results.

METHODS

This study included women at age 31 from prospective population-based Northern Finland Birth Cohort 1966. Serum 25(OH)D concentrations were evaluated between women with or without previous infertility examinations or treatments (infertility group, n = 375, reference group, n = 2051) and time to pregnancy (TTP) of over 12 months (decreased fecundability group, n = 338) with a wide range of confounders. Furthermore, 25(OH)D concentrations were also compared among reproductive outcomes.

RESULTS

The mean 25(OH)D concentration was lower and 25(OH)D < 30 nmol/L was more frequent in women with a history of infertility compared to reference group. Moreover, 25(OH)D > 75 nmol/L was more frequent in the reference group. The mean 25(OH)D concentration was lower in women who had had multiple miscarriages. Both history of infertility (β = -2.7, 95% confidence interval (CI) -4.6, -0.7) and decreased fecundability associated with lower 25(OH)D concentration (β = -4.1, 95% CI -7.4, -0.8) after adjustments. In conclusion, this population-based study demonstrated that previous infertility and decreased fecundability were associated with lower 25(OH)D.

Comparison of Vitamin D Levels and Related Factors in Pregnant Women and Neonates Exposed to Second-Hand Smoke

Introduction: Exposure to second-hand smoke, a significant public health issue today, may lead to various health problems, especially in pregnant women and their infants. Low vitamin D levels during pregnancy may lead to preeclampsia and gestational diabetes in the mother, while it may cause low birth weight and respiratory problems in the infant.

Method: The study group consisted of 42 mothers, who smoked regularly, and their infants and 45 mothers (passive smokers), who were regularly exposed to second-hand smoke in their home environment, although they did not smoke, and their infants. Meanwhile, the control group consisted of 46 healthy mothers, who did not smoke and were not exposed to second-hand smoke at home, and their infants with similar gestational age and birth weight. Blood samples were taken as two different samples, from the mother and the baby, and 25-hydroxyvitamin D (25(OH)D) and related blood parameters were studied and compared statistically.

Results: 25(OH)D, calcium, and magnesium levels of mothers who smoked were significantly lower than those who were exposed to second-hand smoke and those who did not. Moreover, the vitamin D levels of mothers and babies exposed to second-hand smoke in the non-smoker group were significantly lower than mothers and babies who were not exposed to second-hand smoke. In the babies of these three groups, a significant decrease was observed only in vitamin D levels.

Conclusion: The present study shows that pregnant women and their infants exposed to second-hand smoke have lower vitamin D levels. Hence, more emphasis should be put on vitamin D monitoring and supplementation to prevent severe health problems in pregnant women and their infants exposed to tobacco smoke. Further studies are needed to assess the associated risks for maternal and fetal health as well as possible long-term implications for the infant.

Commonalities in Metabolic Reprogramming between Tobacco Use and Oral Cancer

Tobacco use is a major public health concern and is linked to myriad diseases, including cancer. The link between tobacco use and oral cancer, specifically, is very strong, making tobacco use one of the primary risk factors for oral cancer. While this association is well known, the underlying biochemical changes that result from tobacco use, and how this links to metabolic phenotypes of oral cancer, is not well understood. To address this knowledge gap, a combination of literature reviews and metabolomics studies were performed to identify commonalities in metabolic perturbations between tobacco use and oral cancers. Metabolomics analysis was performed on pooled reference urine from smokers and non-smokers, healthy and malignant oral tissues, and cultured oral cells with or without treatment of the well-known tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Alterations in amino acid metabolism, carbohydrates/oxidative phosphorylation, fatty acid oxidation, nucleotide metabolism, steroid metabolism, and vitamin metabolism were found to be shared between tobacco use and oral cancer. These results support the conclusion that tobacco use metabolically reprograms oral cells to support malignant transformation through these pathways. These metabolic reprogramming events may be potential targets to prevent or treat oral cancers that arise from tobacco use.

Smoking Exposure Is Associated with Serum Vitamin D Deficiency in Children: Evidence from the Japan Environment and Children’s Study

Tobacco smoke exposure is known to lower serum 25-hydroxyvitamin D (25(OH)D) concentrations. This study evaluated the association between passive smoking and vitamin D deficiency (VDD) in young children using data from the Japan Environment and Children’s Study (JECS), the largest birth cohort study in Japan. Information on parental smoking status was extracted from a survey of JECS for children aged 1.5 years and data for serum 25(OH)D concentrations were obtained from blood tests in the Sub-Cohort Study of JECS performed at age 2 years. Logistic regression and linear models were fitted to evaluate the association between these variables. Data were analyzed for 4593 children. After adjusting for covariates, smoke exposure was significantly associated with increased incidence of VDD (OR 1.35; 95% CI, 1.14–1.59) according to the logistic model. The linear model indicated that passive smoking negatively predicted de-seasonalized serum 25(OH)D concentrations (β −0.5; 95% CI −0.95 to −0.08) in children aged 2 years. The results suggest that smoke exposure is a risk factor for VDD in children. Given that VD plays a crucial role in bone metabolism and the immune system, our findings are significant for clinical and public health.

Maternal tobacco smoke exposure is associated with increased DNA methylation at human metastable epialleles in infant cord blood

Metastable epialleles (MEs) are genomic regions that are stochastically methylated prior to germ layer specification and exhibit high interindividual but low intra-individual variability across tissues. ME methylation is vulnerable to environmental stressors, including diet. Tobacco smoke (TS) exposure during pregnancy is associated with adverse impacts on fetal health and maternal micronutrient levels as well as altered methylation. Our objective was to determine if maternal smoke exposure impacts methylation at MEs. Consistent with prior studies, we observed reductions in one-carbon pathway micronutrients with gestational TS exposure, including maternal folate (P = 0.02) and vitamins B6 (P = 0.05) and B12 (P = 0.007). We examined putative MEs BOLA3, PAX8, and ZFYVE28 in cord blood specimens from 85 Newborn Epigenetics STudy participants. Gestational TS exposure was associated with elevated DNA methylation at PAX8 (+5.22% average methylation; 95% CI: 0.33% to 10.10%; P = 0.037). In human conceptal kidney tissues, higher PAX8 transcription was associated with lower methylation (R s = 0.55; P = 0.07), suggesting that the methylation levels established at MEs, and their environmentally induced perturbation, may have meaningful, tissue-specific functional consequences. This may be particularly important because PAX8 is implicated in several cancers, including pediatric kidney cancer. Our data are the first to indicate vulnerability of human ME methylation establishment to TS exposure, with a general trend of increasing levels of methylation at these loci. Further investigation is needed to determine how TS exposure-mediated changes in DNA methylation at MEs, and consequent expression levels, might affect smoking-related disease risk.

Perinatal factors and high-sensitive C-reactive protein levels during adolescence

Objective

To examine whether perinatal factors are associated with low-grade inflammation measured by high-sensitivity C-reactive protein levels during adolescence.

Methods

Nested case-control study of 125 teenagers who were born by Cesarean delivery and had high-sensitivity C-reactive protein levels determined at 15–17 years. Data on obstetric and perinatal factors were recorded prospectively at the time of their birth.

Results

Median values of high-sensitivity C-reactive protein were significantly higher in teenagers, who were born as large for gestational age or with maternal diabetes compared to others (2.54 vs 0.34 mg/L; p < 0.024), and born during spring or summer compared to those born during winter or autumn (0.48 vs 0.27 mg/L; p < 0.023). No other perinatal associations were detected (for ex. such as electivity of operation, onset of labor, rupture of fetal membranes, cervical dilatation at delivery, gestational age, Apgar scores at 5 min, umbilical blood pH value, administration of neonatal antibiotics or need of neonatal intensive care treatment) in CRP levels. Further, teenagers with current body mass index in the highest tertile, regular medication for chronic disease and girls using oral contraceptives had significantly higher high-sensitivity C-reactive protein levels than others.

Conclusion

Prenatal exposures such as maternal metabolic environment and seasonality may have longterm effects on the low-grade inflammation and later cardiometabolic risks. Seasonality might be partly explained by maternal vitamin D levels during pregnancy, and thus future efforts are warranted to ensure sufficient vitamin D availability during pregnancy. Surprisingly, no other significant associations were detected between perinatal characteristics and high-sensitivity C-reactive protein levels.

Maternal Vitamin D Levels During Pregnancy and Offspring Autism Spectrum Disorder

BACKGROUND

Findings from previous studies on maternal 25-hydroxyvitamin D [25(OH)D] levels during pregnancy and autism spectrum disorder (ASD) in offspring are inconsistent.

METHODS

The association between maternal 25(OH)D levels during pregnancy and offspring ASD was examined using data from a nationwide population-based register with a nested case-control study design. The ASD cases (n = 1558) were born between 1987 and 2004 and received a diagnosis of ASD by 2015; cases were matched with an equal number of controls. Maternal 25(OH)D levels during pregnancy were measured using quantitative immunoassay from maternal sera collected during the first and early second trimesters and archived in the national biobank of the Finnish Maternity Cohort. Conditional logistic regression examined the association between maternal 25(OH)D levels and offspring ASD.

RESULTS

In the adjusted model, there was a significant association between increasing log-transformed maternal 25(OH)D levels and decreasing risk of offspring ASD (adjusted odds ratio [aOR] 0.75, 95% confidence interval [CI] 0.62-0.92, p = .005). Analyses by quintiles of maternal 25(OH)D levels revealed increased odds for ASD in the 2 lowest quintiles, <20 (aOR 1.36, 95% CI 1.03-1.79, p = .02) and 20-39 (aOR 1.31, 95% CI 1.01-1.70, p = .04), compared with the highest quintile. The increased risk of ASD was observed in association with deficient (<30 nmol/L) (aOR 1.44, 95% CI 1.15-1.81, p = .001) and insufficient (30-49.9 nmol/L) maternal 25(OH)D levels (aOR 1.26, 95% CI 1.04-1.52, p = .01) compared with sufficient levels.

CONCLUSIONS

This finding has implications for understanding the role of maternal vitamin D during fetal brain development and increased risk of ASD.

Smoking behavior and circulating vitamin D levels in adults: A meta-analysis

To determine the effect of smoking on circulating vitamin D in adults, we performed a meta-analysis. Literature before 9 May 2021 was retrieved from electronic literature databases such as EMBASE, PubMed, and Cochrane. The quality of the included studies was assessed by two researchers against the Newcastle-Ottawa scale and JBI Evidence-based Health Care Centre criteria. All eligible studies and statistical analyses were performed using STATA 14. Twenty-four studies with 11,340 participants meeting the criteria were included in the meta-analysis. The results of meta-analysis showed that the level of circulating 25(OH)D in smokers was lower than that in nonsmokers. A subgroup analysis based on vitamin D supplement use showed that both smokers who used vitamin D supplements and smokers who did not use vitamin D supplements had lower blood 25(OH)D levels compared with the control group. In addition, subjects were divided into different subgroups according to age for meta-analysis, and the results showed that the serum 25(OH)D level in each subgroup of smokers was lower than that in the control group. This meta-analysis revealed differences in circulating vitamin D levels between smokers and nonsmokers, with smokers likely to have lower circulating vitamin D levels.

Maternal Vitamin D Levels and the Risk of Offspring Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Recent evidence has highlighted the importance of vitamin D in the development of the central nervous system. Some studies have shown an association between maternal vitamin D deficiency during pregnancy and offspring attention-deficit/hyperactivity disorder (ADHD) symptoms based on parent or teacher ratings. There are no previous studies on early pregnancy 25-hydroxyvitamin D [25(OH)D] levels and the risk of diagnosed offspring ADHD. Our aim was to examine maternal 25(OH)D levels in early pregnancy and offspring ADHD.

METHOD

In this nationwide population-based case-control study, 1,067 ADHD cases (born between 1998 and 1999 and diagnosed according to the International Classification of Diseases) and 1,067 matched controls were identified from Finnish registers. Maternal 25(OH)D levels were measured using quantitative immunoassay from maternal sera, collected during the first trimester and archived in the national biobank. Conditional logistic regression was used to examine the association between maternal 25(OH)D and offspring ADHD.

RESULTS

There was a significant association between decreasing log-transformed maternal 25(OH)D levels and offspring ADHD both in the unadjusted analyses (odds ratio 1.65; 95% CI 1.33-2.05; p < .001) and in the analyses adjusting for maternal socioeconomic status and age (odds ratio 1.45; 95% CI 1.15-1.81; p = .002). Analyses by quintiles of maternal 25(OH)D levels in the lowest versus highest quintile revealed an adjusted odds ratio for offspring ADHD of 1.53 (95% CI 1.11-2.12; p = .010).

CONCLUSION

This study demonstrated an association between low maternal 25(OH)D during pregnancy and an elevated risk for offspring ADHD. If replicated in independent samples, this finding may have significant public health implications.