Vitamin D deficiency in adolescent pregnancy and obstetric outcomes

Does adolescent pregnancy affect postmenopausal bone mineral density?

Aim: This study aims to investigate the effect of adolescent pregnancies on bone mineral density in the postmenopausal period and to contribute to this controversial issue. Material and Method: Our study included 70 women at postmenopausal ages. The participants were divided into two groups. Thirty-five women with a history of pregnancy in adolescence were considered group 1, and 35 women without a history of pregnancy were considered group 2. The BMD was measured in the total hip, femoral neck, and lumbar spine. The data were compared using SPSS version 26, and p

Effect of maternal vitamin D status on risk of adverse birth outcomes: a systematic review and dose-response meta-analysis of observational studies

PURPOSE

Accumulating evidence suggests that vitamin D deficiency increases the risk of adverse perinatal outcomes. However, the dose-response relationship between maternal vitamin D status and adverse birth outcomes remains unclear. Focusing on prospective observational studies, we aimed to explore the dose-response relationship of vitamin D status with the risk of low birth weight (LBW), macrosomia (MA), preterm birth (PTB), small for gestational age (SGA), and intrauterine growth restriction (IUGR).

METHODS

Databases including PubMed, Embase, Scopus, and Web of Science were used up to 19 January 2021 to search for observational studies that fulfilled criteria as follows: cohort studies, case-cohort studies, or nested case-control studies. Random-effects models were used to pool relative risks (RRs) and 95% confidence intervals (CIs) in the observational studies.

RESULTS

A total of 72 publications were included in this systematic review and 71 in the meta-analysis. Maternal 25-hydroxyvitamin D (25(OH)D) concentrations were inversely associated with the risk of LBW (RR: 0.65; 95% CI 0.48-0.86), PTB (RR: 0.67; 95% CI 0.57-0.79), and SGA (RR: 0.61; 95% CI 0.49-0.76) in the highest versus lowest meta-analysis, but not associated with MA and IUGR. Linear dose-response analysis showed that each 25 nmol/L increase in 25(OH)D was associated with a 6% and 10% reduction in the risk of PTB (RR: 0.94; 95% CI 0.90-0.98) and SGA (RR: 0.90; 95% CI 0.84-0.97), respectively.

CONCLUSION

Our study suggests that a sufficient vitamin D status during pregnancy is protective against the risk of LBW, PTB, and SGA.

Association between maternal vitamin D levels and risk of adverse pregnancy outcomes: a systematic review and dose-response meta-analysis

Epidemiological studies have investigated the associations between vitamin D and the risk of adverse pregnancy outcomes; however, the results are conflicting and dose-response relationships remain to be confirmed. This study aimed to summarize previous studies on the associations of vitamin D levels with the risk of gestational diabetes mellitus (GDM), pre-eclampsia (PE), gestational hypertension (GH), and caesarean section (C-section), and to clarify the dose-response trends. PubMed, Embase, Scopus, and Web of Science were searched to identify eligible articles. A total of 69 prospective observational studies including cohort studies, case-cohort studies, or nested case-control studies were included in the current systematic review, of which 68 studies were available for meta-analysis. Compared with the lowest level, the highest level of 25(OH)D was significantly associated with a lower risk of GDM (RR: 0.76; 95% CI: 0.66-0.87), PE (RR: 0.74; 95% CI: 0.60-0.90;), and GH (RR: 0.87; 95% CI: 0.79-0.97); however, no significant relationship was found for C-section (RR: 1.00; 95% CI: 0.90-1.12). There was significant between-study heterogeneity for GDM (I² = 69.2%; P_{heterogeneity} < 0.001), PE (I² = 52.0%; P_{heterogeneity} = 0.001), and C-section (I² = 59.1%; P_{heterogeneity} < 0.001), while no heterogeneity was found for GH (I² = 0.0%; P_{heterogeneity} = 0.676). For each 25 nmol L^-1 increase in 25(OH)D, the pooled RR was 0.92 (95% CI: 0.86-0.97) for GDM and 0.89 (95% CI: 0.84-0.94) for PE, respectively. Notably, the dose-response analysis showed a non-linear relationship between maternal 25(OH)D levels and the risk of PE (P_{non-linearity} = 0.009). Our meta-analysis provides further scientific evidence of the inverse association between 25(OH)D levels and the risk of GDM, PE, and GH, which may be useful for the prevention of pregnancy complications. However, more evidence from prospective studies is needed regarding the dietary intake of vitamin D during pregnancy.

Impact of vitamin D on the course of COVID-19 during pregnancy: A case control study

OBJECTIVE

We aimed to evaluate the vitamin D status of pregnant women with COVID-19, and the association between vitamin D level and severity of COVID-19.

METHODS

In this case control study, 159 women with a single pregnancy and tested positive for SARS-CoV-2, and randomly selected 332 healthy pregnant women with similar gestational ages were included. COVID-19 patients were classified as mild, moderate, and severe. Vitamin D deficiency was defined as 25-hydroxycholecalciferol <20 ng/mL (50 nmol/L), and 25-OH D vitamin <10 ng/mL was defined as severe vitamin D deficiency, also 25-OH D vitamin level between 20-29 ng/mL (525-725 nmol/L) was defined as vitamin D insufficiency.

RESULTS

Vitamin D levels of the pregnant women in the COVID-19 group (12.46) were lower than the control group (18.76). 25-OH D vitamin levels of those in the mild COVID-19 category (13.69) were significantly higher than those in the moderate/severe category (9.06). In terms of taking vitamin D supplementation, there was no statistically significant difference between the groups. However, it was observed that all of those who had severe COVID-19 were the patients who did not take vitamin D supplementation.

CONCLUSION

The vitamin D levels are low in pregnant women with COVID-19. Also, there is a significant difference regarding to vitamin D level and COVID-19 severity in pregnant women. Maintenance of adequate vitamin D level can be useful as an approach for the prevention of an aggressive course of the inflammation induced by this novel coronavirus in pregnant women.

Vitamin D status and healthy Egyptian adolescents: Where do we stand?

Vitamin D deficiency is a worldwide public health problem. Low vitamin D and its consequences among children and adolescents could be considered as one of the most important health-related problems. This study aimed to estimate the prevalence of vitamin D deficiency in healthy Egyptian adolescents and investigate factors associated with vitamin D status.A cross-sectional study was conducted on 572 school children (270 males and 302 females) aged 14 to 18 years, who were randomly selected from high schools in one governorate in Egypt. Data were collected through a self-administered questionnaire. Vitamin D level, serum calcium, phosphorus, alkaline phosphates were measured.Vitamin D deficiency was almost present in all the studied Egyptian healthy adolescents (99%), 94.8% had vitamin D deficiency and 4.2% had vitamin D insufficiency. Girls had a higher prevalence of vitamin D deficiency than boys. There was a significant association between lack of physical activity, sun exposure, and vitamin D deficiency.Vitamin D deficiency and insufficiency are highly prevalent. In sunny countries, the special pattern of conservative clothing and the lack of outdoor physical activity might be the underlying factors for the high prevalence in females. Vitamin D supplementation seems to be mandatory to halt the problem.

Large retrospective cohort study of the association between maternal 25-hydroxyvitamin D status and birth weight of neonate

BACKGROUND

The effect of maternal vitamin D levels on the birth weight of the offspring remains controversial, as the results are inconsistent between different populations. This large retrospective cohort study aimed to assess the relationship between maternal vitamin D levels and birth weight of neonates in southern China.

METHODS

Serum samples were collected from 10,586 Chinese women at 13-27 weeks of pregnancy, and the 25-hydroxyvitamin D (25(OH)D) level of the participants was assessed. Using the INTERGROWTH-21st standards, the offspring were classified into three groups based on their gestational age and birth weight, which were small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA). The differences in vitamin D levels among the different groups were compared, and their correlation with newborn birth weight was analyzed.

RESULTS

The average maternal vitamin D concentration was 61.1 nmol/L. The 25(OH)D concentrations were 50-75 nmol/L, 25-50 nmol/L and below 25 nmol/L in 45.5%, 29.5%, and 1.6% of the participants, respectively. No significant differences were observed in the vitamin D levels between the three groups. With the increase in 25(OH)D levels, the risk of SGA and LGA tended to increase and decrease, respectively. AGA was not affected by the 25(OH)D levels. The results of the curve fitting and threshold effect analyses did not support the correlation between vitamin D levels and SGA or LGA. Based on the univariate prediction model and the model adjusted for risk factors, the area under the curve was extremely small. Thus, 25(OH)D levels are not an effective predictor of SGA and LGA.

CONCLUSIONS

Low maternal vitamin D levels were not associated with SGA or LGA.