To clarify nutrient supplementation usage and primary source of information among pregnant women in China.

This cross-sectional study used information on nutrient supplementation and primary source of information collected via face-to-face interviews. Data on the usage of folic acid, Ca/vitamin D, Fe, vitamins, DHA and other dietary supplements were collected. Primary source of information was categorised as family/relatives, friends/co-workers, the Internet, books/magazines, television/radio, doctors, other people and oneself.

Maternal and Child Health Hospital in Chengdu, China.

One thousand eighty-one Chinese pregnant women aged ≥20 years with singleton pregnancies.

In all three trimesters of pregnancy, usage was highest and most stable for folic acid (81·7 %), followed by vitamins (vitamin A, B-group vitamins, vitamin C and multivitamins; 75·0 %), whereas Ca/vitamin D (51·4 %) and Fe (18·1 %) usage was low, potentially indicating a deficiency risk. All supplementation usage percentages increased with pregnancy duration (P < 0·05). Notably, approximately 10 % of the pregnant women in our study did not use any nutrient supplementation, and this was especially common in early pregnancy. More than 50 % of the women reported getting information on nutrient supplementation from family members, and about 30 % reported getting this information from doctors.

Among pregnant women in China, awareness about nutrient supplementation increases as the pregnancy progresses, but some types of nutrient supplementation (such as Ca/vitamin D and Fe) remain at low levels. It is necessary to pay more attention to the health education of pregnant women in China, and the influence of family members should be emphasised.

To determine which set of BMI cut-offs is the most appropriate to define child and adolescent obesity in urban China.

A cross-sectional study was carried out between 1 November and 31 December in 2017.

Community Healthcare Center in Minhang District, Shanghai, China.

A total of 12 426 children and adolescents aged 7–17 years were selected by cluster random sampling. Bioelectrical impedance analysis was the gold standard to measure body composition.

Comparisons of three sets of BMI cut-offs by sensitivity and κ value revealed that the Working Group on Obesity in China (WGOC) (sensitivity 39·9–84·0 %; κ 0·51–0·79) and WHO (sensitivity 25·5–74·5 %; κ 0·35–0·78) cut-offs were not superior to the International Obesity Task Force (IOTF) (sensitivity 47·9–92·4 %; κ 0·58–0·85) cut-offs across all subgroups. The WGOC and WHO cut-offs yielded higher misclassification rates, in the worst case, categorising 11·2 % of girls with high adiposity as normal and 44·4 % of them as overweight, while the IOTF cut-offs categorised 2·3 % as normal and 30·7 % as overweight. Individuals who were classified by the IOTF cut-offs as overweight had the lowest ratios of high adiposity (4·2–41·6 %) than by the BMI cut-offs for each subgroup. Among pubertal girls, none of the BMI-based cut-offs indicated excellent agreement with body fat percentage, and κ value of the WHO cut-offs (0·35 (95 % CI 0·29, 0·41)) was lower than the other two sets of BMI cut-offs (all P < 0·001).

The IOTF cut-offs for Asian should be recommended for child obesity screening in urban China. Pubertal individuals need a more accurate indicator of obesity screening.