This experiment was conducted to investigate whether dietary chenodeoxycholic acid (CDCA) could attenuate high-fat (HF) diet-induced growth retardation, lipid accumulation and bile acid (BA) metabolism disorder in the liver of yellow catfish Pelteobagrus fulvidraco. Yellow catfish (initial weight: 4·40 (sem 0·08) g) were fed four diets: the control (105·8 g/kg lipid), HF diet (HF group, 159·6 g/kg lipid), the control supplemented with 0·9 g/kg CDCA (CDCA group) and HF diet supplemented with 0·9 g/kg CDCA (HF + CDCA group). CDCA supplemented in the HF diet significantly improved growth performance and feed utilisation of yellow catfish (P < 0·05). CDCA alleviated HF-induced increment of hepatic lipid and cholesterol contents by down-regulating the expressions of lipogenesis-related genes and proteins and up-regulating the expressions of lipololysis-related genes and proteins. Compared with the control group, CDCA group significantly reduced cholesterol level (P < 0·05). CDCA significantly inhibited BA biosynthesis and changed BA profile by activating farnesoid X receptor (P < 0·05). The contents of CDCA, taurochenodeoxycholic acid and glycochenodeoxycholic acid were significantly increased with the supplementation of CDCA (P < 0·05). HF-induced elevation of cholic acid content was significantly attenuated by the supplementation of CDCA (P < 0·05). Supplementation of CDCA in the control and HF groups could improve the liver antioxidant capacity. This study proved that CDCA could improve growth retardation, lipid accumulation and BA metabolism disorder induced by HF diet, which provided new insight into understanding the physiological functions of BA in fish.

Most childhood disabilities are caused by congenital factors such as birth defects. The present study aims to evaluate the effect of periconceptional nutrition intervention on the prevention of congenital disability among Chinese children using the National Birth Defects Intervention Project as a natural experiment. We obtained individual-level data from the Second National Sample Survey on Disability, a nationally representative survey, and 110 365 children born between September 1999 and August 2003 were included for analysis. Difference-in-differences estimates of the project effects on congenital disability were captured by exploiting temporal variation in the timing of project exposure across four birth cohorts along with geographical variation in project category at the province level. The findings contribute to an emerging body of evidence showing that prenatal micronutrient intervention before and during early pregnancy could substantially reduce the risk of congenital disability in childhood (OR 0·73; 95 % CI 0·57, 0·94). The National Birth Defects Intervention Project improved the awareness of reproductive health and disability prevention in the population. It highlights the need for a potential policy change focusing on early-life health investment in China.

The current measures of cognitive functioning in adulthood do not indicate a long-term association with prenatal exposure to the Dutch famine. However, whether such association emerges in China is poorly understood. We aimed to investigate the potential effect of prenatal exposure to the 1959–1961 Chinese famine on adult cognitive impairment. We obtained data from the Second National Sample Survey on Disability implemented in thirty-one provinces in 2006, and restricted our analysis to 387 093 individuals born in 1956–1965. Cognitive impairment was defined as intelligence quotient (IQ) score under 70 and IQ of adults was evaluated by the Wechsler Adult Intelligence Scale – China Revision. Famine severity was defined as excess death rate. The famine impact on adult cognitive impairment was estimated by difference-in-difference models, established by examining the variations of famine exposure across birth cohorts. Results show that compared with adults born in 1956–1958, those who were exposed to Chinese famine during gestation (born in 1959–1961) were at greater risk of cognitive impairment in the total sample. Stratified analyses showed that this effect was evident in males and females, but only in rural, not in urban areas. In conclusion, prenatal exposure to famine had an enduring deleterious effect on risk of cognitive impairment in rural adults.

Chinese youth represent a high-risk group for sexually transmitted infections and unintended pregnancies, but there is little understanding of their sexual behaviours. Using nationally representative data, this study examines the social and demographic correlates of condom use by Chinese youth at sexual debut. It also examines the relationship context of condom use at sexual debut. The results indicate that condom use at sexual debut is very low in China, confirming that youth are a high-risk group. The results demonstrate that age and educational attainment are the primary indicators of condom use. Early sexual debut associates with a greater risk of unsafe sex at sexual debut and higher educational attainment increases the likelihood of self-protecting behaviours. The likelihood of self-protection also increases when sexual partners plan their sexual debut or discuss contraception beforehand. The results suggest that interventions are needed to provide youth with better knowledge about self-protection.