Adequate Dietary Intake and Vitamin D Supplementation: A Study of Their Relative Importance in Determining Serum Vitamin D and Ferritin Concentrations during Pregnancy.

Vitamin D is essential for human health. However, it is not clear if vitamin D supplementation is necessary for all pregnant women. This study examines the relative importance of dietary patterns and vitamin D supplementation frequency in determining serum 25-hydroxyvitamin D (25(OH)D) and ferritin concentrations among pregnant women in Hong Kong, China. A total of 572 healthy women were recruited from antenatal clinics at 25-35 weeks pregnant. Participants completed an electronic version of the food frequency questionnaire and a web questionnaire on supplement use. Their blood samples were tested for serum 25(OH)D and ferritin. The associations of dietary patterns and vitamin D supplementation frequency with serum 25(OH)D and ferritin concentrations were analyzed using moderated hierarchical regression. Two dietary patterns were identified. The adequate dietary intake was characterized by the high probability of meeting recommended daily food group servings, whereas the inadequate dietary intake was characterized by inadequate consumption of vegetables, fruits, meat, fish, and eggs, or alternatives. The association between adequate dietary intake and serum ferritin concentrations was independent of vitamin D supplementation frequency (ß = 0.05, p = 0.035), but dietary patterns interacted with vitamin D supplementation frequency to determine serum 25(OH)D concentrations (ß = -13.22, p = 0.014). The current study presents evidence on the relative importance of dietary patterns and vitamin D supplementation in maintaining sufficient vitamin D and iron in pregnancy. Antenatal nutrition counselling services should be provided to pregnant women who show signs of inadequate dietary intake.

Vitamin D concentrations during pregnancy and in cord blood: a systematic review and meta-analysis.

CONTEXT: Effect size estimates for the association between vitamin D concentrations in maternal blood during pregnancy and in cord blood vary widely across studies, but no meta-analysis has been conducted to ascertain this association. OBJECTIVE: The aim of this systematic review was to estimate the pooled effect size for the association between circulating 25-hydroxyvitamin D (25[OH]D) concentrations, a marker of vitamin D status, in maternal blood during pregnancy and in cord blood. DATA SOURCES: The PubMed, Embase, and Web of Science databases were searched from their inception to February 2021. DATA EXTRACTION: Following the application of prespecified inclusion and exclusion criteria, 94 articles were eligible for full-text review, which was conducted by 2 authors independently. A third author was consulted when necessary and consensus reached. In total, 26 articles, which comprised 30 studies and 6212 mother-infant dyads, were included. Methodological quality was assessed using a modified version of the Joanna Briggs Institute's Critical Appraisal Checklist for Studies Reporting Prevalence Data. Correlation coefficient (r) values for the association between maternal serum 25(OH)D concentrations during pregnancy and in cord blood were extracted. DATA ANALYSIS: The r values were pooled using random-effects meta-analyses. Sensitivity and subgroup analyses were performed to investigate sources of heterogeneity. The pooled r for all studies was 0.72 (95%CI, 0.64-0.79), indicating high heterogeneity (I2 = 95%, P < 0.01). After influential and outlier studies were removed, the pooled r for 9 studies was 0.70 (95%CI, 0.66-0.74), which resulted in a substantial reduction in heterogeneity (I2 = 41%, P=0.10). CONCLUSION: The findings support a positive and large correlation between maternal vitamin D concentrations during pregnancy and vitamin D concentrations in cord blood. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number CRD42021273348.

An Assessment of Risk Factors for Insufficient Levels of Vitamin D during Early Infancy.

Recent evidence suggests that breastfeeding may increase the risk of vitamin D deficiency in offspring. However, it is unclear whether increased risk results from breastfeeding alone, or whether it is associated together with other risk factors. This study surveyed 208 infant-mother dyads recruited by stratified random sampling in different districts of Hong Kong. Mothers were asked to complete a questionnaire on their demographics, history of risk behavior, and feeding practices. Peripheral blood samples were collected from infants to determine their vitamin D status. Among all infant participants, 70 were vitamin D insufficient or deficient. Being breastfed, being a girl, having a multiparous mother, and the use of sun cream were found to be the strongest risk factors for vitamin D insufficiency during infancy (all p < 0.05), after mutual adjustment. The cumulative risk model displayed a dose-response pattern between the number of risk factors and the risk of vitamin D insufficiency during this period. Our findings indicate the risk profile of infants with insufficient vitamin D. Guidelines and recommendations on healthy diet and lifestyle should be provided to mothers during the early stage of pregnancy to increase the likelihood of adequate levels of vitamin D in their offspring.

Examining the Cervical Screening Behaviour of Women Aged 50 or above and Its Predicting Factors: A Population-Based Survey.

Under-screening may increase the risk of cervical cancer in middle-aged women. This study aimed to investigate cervical cancer screening behaviour and its predictors among women aged 50 years or above. A population-based sample of 959 women was recruited by telephone from domestic households in Hong Kong, using random methods, and a structured questionnaire developed to survey participants. Multivariable logistic regressions were performed to examine the factors independently associated with cervical screening behaviour. Nearly half the sample (48%) had never had a cervical smear test. Multivariable analyses showed that age, educational level, marital status, family history of cancer, smoking status, use of complementary therapy, recommendation from health professionals, and believing that regular visits to a doctor or a Chinese herbalist were good for their health were predictors of cervical screening behaviour. Misconceptions concerned with menopause may reduce women's perceived susceptibility to cervical cancer, especially if they are 50 or above, and exert a negative effect on their screening behaviour. Healthcare professionals should actively approach these high-risk groups-older unmarried women, smokers, those less educated and who are generally not much concerned with their health.