Vitamin D deficiency is associated with numerous public health issues. Limited data are available for children in southern China, a region that receives abundant sunlight. We aimed to estimate the 25-hydroxyvitamin D (25(OH)D) levels in children in that area, and to determine seasonal variations in serum 25(OH)D levels. A total of 16,755 children aged 0 to 6 years, who visited the Guangdong Women and Children's Hospital for health examination between January 2016 and May 2017, were included in the present study. The serum 25(OH)D levels ranged from 10.5 to 307.4 nmol/L (mean ± standard deviation: 78.5 ± 26.3 nmol/L). The prevalence of vitamin D deficiency and insufficiency were 10.8% and 39.0%, respectively. The mean serum 25(OH)D level in spring (71.8 ± 24.9 nmol/L) was lower than that in other seasons. From January to April, we found a relatively high prevalence of vitamin D deficiency or insufficiency, both of which were also found to increase with age. Logistic regression analysis revealed that vitamin D deficiency and insufficiency were significantly associated with age and season. Deficiency and insufficiency of vitamin D are common among children in southern China, despite the area receiving sufficient sunlight.

Background: Cow's milk protein allergy (CMPA) is commonly seen in children. There have been no reports of the true prevalence of CMPA in Chinese infants. The aim of this population‐based study is to determine the prevalence, clinical characteristics, and outcome of CMPA in Chinese infants. Methods: We carried out a prospective survey in 7 participating hospitals throughout southern China. We included infants ≤12 months of age during the survey. For those suspected of CMPA, oral food challenge with cow's milk protein (CMP) was performed. A follow‐up telephone interview was conducted at 12 months after the diagnosis to assess the clinical outcome of CMPA. Results: A total of 9910 questionnaire surveys were distributed and 7364 (74.3%) were returned. The eligible survey number of surveys was 6768 (91.9%). A total of 182 infants was confirmed with CMPA, including 13 with anaphylactic reactions, 28 with clinical symptoms and serum immunoglobulin E (sIgE) >3.5 IU/mL, and 141 with positive CMP challenge test. The prevalence of CMPA was 2.69%. Infants with confirmed CMPA had significantly stronger family history of either 1 or both parents with food allergy, higher Cesarean section rate, and lower rate of breastfeeding, compared with those without CMPA. At 12‐month telephone follow‐up of 176 CMPA infants, 136 infants (77.3%) had become tolerant to CMP. Conclusions: The prevalence of CMPA was 2.69%. CMPA infants had a strong family history of food allergy and atopy. Both Cesarean delivery and formula feeding were risk factors for CMPA. At 12‐month follow‐up, the majority of CMPA infants had become tolerant to CMP.

Departmental sources Background: The influence of maternal vitamin D on pregnancy outcomes, including preterm birth (PTB), is unclear due to different experimental designs and study populations (patient race and sample size) of previous studies. We aimed to investigate the relationship between 25-hydroxyvitamin D (25[OH] D) levels and PTB among pregnant women in southern China. Material/Methods: A total of 11 641 pregnant women were retrospectively enrolled between January 2016 and April 2019. Vitamin D concentrations were evaluated by electrochemiluminescence immunoassay. Logistic regression analysis was used to analyze the association between vitamin D and PTB. Results: The average 25(OH) D concentration was 59.3±21.5 nmol/L; 34.8% of patients were vitamin D deficient, 43.0% were vitamin D insufficient (25[OH] D <50 nmol/L and 50-74.9 nmol/L, respectively). In total, 3.6% of newborns were born prematurely. Comparing the pre-term and full-term groups, 45.7% versus 42.9% and 29.8% versus 35% were vitamin D deficient and insufficient, respectively These differences were not significant (P>0.05). However, the mean vitamin D status was significantly different between the pre-term and full-term groups (61.3±21.3 and 59.1±21.5 nmol/L, respectively). No association was found between vitamin D deficiency/insufficiency and PTB in unadjusted or adjusted models, compared with vitamin D sufficiency (adjusted odds ratio, 1.016; 95% confidence interval, 0.794-1.301 and 0.842; 0.641-1.106, respectively). Conclusions: Low maternal 25(OH) D levels are common in southern China. However, low vitamin D status in pregnant women appears to be unrelated to PTB. Measuring vitamin D level alone is therefore not sufficient to predict PTB.

No abstract