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Objective@#To investigate the prospective effects of the consumption of protein and animal foods before menarche on the age at menarche among Chinese girls.@*Methods@#This paper was based on the data collected in the China Health and Nutrition Survey(CHNS) from 1997 to 2015. A total of 683 girls aged 6 and over who had completed information on age at menarche, height, weight, per capita annual household income, maternal education level and participated in at least one complete dietary survey within 1 to 4 years before menarche were included. Urban-rural stratified multivariable linear regression model was used to examine the effects of protein and animal foods intake before menarche on Chinese girls age at menarche in urban and rural areas.@*Results@#After adjusted for total energy intake, body mass index standard deviation score and per capita annual household income, the consumption of meat before menarche was negatively associated with the age at menarche among rural Chinese girls(B=-0.003, P=0.00), but not among urban Chinese girls(B=0.002, P>0.05). Total protein, dairy, eggs and aquatic products intake before menarche were not associated with Chinese girls age at menarche in urban and rural areas(B=0.002, -0.001, 0.003, 0.000; 0.001, 0.001, -0.001, -0.003, P>0.05).@*Conclusion@#Higher intake of meat before menarche might lead to earlier menarche onset in rural Chinese girls. The consumption of total protein, dairy, eggs, and aquatic products before menarche did not affect the age at menarche in Chinese girls.
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Objective@#To explore the relationship between premenarchal dietary carbohydrate and dietary fiber intakes and age at menarche in Chinese girls.@*Methods@#Based on dietary and menarcheal information on 750 girls from the Chinese Health and Nutrition Survey, multivariate linear regression models and logistic models were used to analyze the influence of dietary carbohydrate and dietary fiber intakes before menarche onset and age at menarche. Carbohydrate intake was replaced by engergg ratio carbohydrate for a sensitivity analysis.@*Results@#Adjusting for residence, per capita household income, body mass index standard deviation score, and energy intake, higher intake and higher energy ratio of carbohydrate were associated with later age at menarche(P<0.01). Compared to girls at the lowest tertile of carbohydrate intake level, those at the highest tertile had a 0.35 years(2.8%) delay in age at menarche, while 55% decreased[OR(95%CI)=0.45(0.30-0.69)]. Dietary fiber intake was not associated with age at menarche in any model(P>0.2).@*Conclusion@#Girls with higher premenarcheal carbohydrate intake experienced menarche later, while dietary fiber intake was not associated with age at menarche.
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BACKGROUND: Heavy metals can cause great harm to Siberian tigers in the natural environment. Cadmium (Cd2+) is an environmental contaminant that affects multiple cellular processes, including cell proliferation, differentiation, and survival. It has been shown to induce apoptosis in a variety of cell types and tissues. RESULTS: We investigated the apoptotic effects of Cd2+ on Siberian tiger fibroblasts in vitro. Our research revealed the typical signs of apoptosis after Cd²+ exposure. Apoptosis was dose- (0-4.8 µM) and duration-dependent (12-48 h), and proliferation was strongly inhibited. Cd²+ increased the activity of caspase-3, -8, and -9 and disrupted calcium homeostasis by causing oxidative stress and mitochondrial dysfunction. It also increased K+ efflux and altered the mRNA levels of Bax, Bcl-2, caspase-3, caspase-8, Fas, and p53. CONCLUSIONS: Our results suggest that Cd2+ triggers the apoptosis of Siberian tiger fibroblasts by disturbing intracellular homeostasis. These results will aid in our understanding of the effects of Cd2+ on Siberian tigers and in developing interventions to treat and prevent cadmium poisoning.