Status and correlates of children's exposure to secondhand smoke at home: A survey in Chongqing, China.

INTRODUCTION: The home is the primary source of children's exposure to secondhand smoke. This study investigated the status and influencing factors of child exposure to secondhand smoke at home when people smoke in the household. METHODS: Participants with at least one child living in their household from 10 communities in Chongqing were recruited and provided a self-administered questionnaire using a multistage proportional random sampling design from June to August 2021. The chi-squared test and binary logistic regression analyses were used to identify influencing factors. RESULTS: The questionnaire completed by 1345 families showed that 631 (46.9%) families lived with smokers in their household, and 509 (80.7%) of those families reported that smoking occurred within the home while the children were present. Binary logistic regression analyses demonstrated that the time between waking up and household smokers having the first cigarette of the day (OR=0.44; 95% CI: 0.22-0.85), changes to smoking habits and behaviors within the last six months (OR=1.76; 95% CI: 1.06-2.90), attitudes towards tobacco control in the household (OR=2.91; 95% CI: 1.72-4.92), self-efficacy in maintaining a smoke-free home (OR=2.27; 95% CI: 1.36-3.79), having rules to maintain a smoke-free home (OR=3.25; 95% CI: 1.68-6.29), and the status of providing cigarettes to guests at home (OR=11.0; 95% CI: 1.33-90.8) were associated with exposure to SHS. CONCLUSIONS: Education focusing on the impact of smoking on children's health should be encouraged. Smoke-free homes should be established, and smoking restrictions in the household should be enacted. Therefore, information about the available tobacco-control services should be given to family members and be used properly. It is an effective way to decrease the risk of at-home exposure to SHS for children, to overcome any obstacles in tobacco control.

Rapamycin inhibits spermatogenesis by changing the autophagy status through suppressing mechanistic target of rapamycin-p70S6 kinase in male rats.

Rapamycin (sirolimus) is an antiproliferative drug that has been widely used in the clinic as an immunosuppressant and a potential anticancer agent. Certain reports have indicated that rapamycin may induce male infertility through impairing sperm quality. The present study investigated the mechanism of male infertility caused by rapamycin and examined whether withdrawal of rapamycin could recover the number of sperm in rats. Male Sprague­Dawley rats (n=100) were divided randomly into 5 groups: 3 rapamycin­treated groups (2, 4 and 6 mg/kg) and 2 control groups [Blank and dimethyl sulfoxide (DMSO)]. Organ coefficients of the testes, number of sperm and hematoxylin­eosin staining analyses demonstrated that rapamycin treatment markedly damaged the structure of the seminiferous tubule and reduced the number of sperm. Immunohistochemistry of mechanistic target of rapamycin (mTOR) and Ki67 in testes tissue, and western blotting of phosphorylated­p70S6K and p70S6K, supported the hypothesis that rapamycin causes sperm reduction through inhibiting proliferation of spermatogonia. Unfortunately, 24 weeks after cessation of rapamycin treatment, only the number of sperm in 2 mg/kg group was restored back to the normal level. In addition, to the best of our knowledge, the present study was the first to demonstrate that low doses rapamycin leads to activation of autophagy in rat testes. This may be a self­protective mechanism of the cell in response to external stress. Thus, spermatogenesis can be recovered in the testes from rats in the low dose group. High doses of rapamycin resulted in excessive consumption of autophagy proteins, and the damage could not be compensated. In addition, it was revealed that cell apoptosis increased after treatment with rapamycin. In conclusion, the present study demonstrated that rapamycin inhibits spermatogenesis through suppressing phosphorylation of p70S6K and changing the autophagy status, ultimately reducing the number of sperm. These findings provide important guidance for the clinical application of rapamycin.