Secondhand smoke is associated with heavy metal concentrations in children

Secondhand smoke (SHS) has adverse effects on health, particularly for children. Our purpose was to analyze the correlation between SHS exposure and heavy metal concentrations in children. The investigation was conducted in Xinxiang County, Henan Province, China, from August 2015 to December 2015. In total, 821 students (433 boys and 388 girls) were recruited, and the contents of heavy metals in their hair—including chromium, manganese, nickel, arsenic, lead, and cadmium—were detected by ICP-MS. The children’s parents were informed, and a questionnaire was conducted, which included questions about smoking habits and demographic characteristics. Our results indicate that all parent smokers are fathers, 48.9% of fathers who are smokers, but 25.2% of fathers smoke in front of their children. The levels of chromium (median girls vs boys, μg/g) (2.36 vs 2.06, p  < 0.001), nickel (1.28 vs 0.97, p  < 0.001), arsenic (0.55 vs 0.49, p  < 0.001), and lead (2.73 vs 2.16, p  < 0.001) in girls were significantly higher than in boys. The levels of cadmium (median, SHS group vs control: 0.43 vs 0.29 (μg/g), p  < 0.001) and lead (median, SHS group vs control: 2.71 vs 2.27 (μg/g), p  = 0.007) in the SHS group were significantly higher than in the control. Multi-linear regression analysis indicated that SHS exposure in children is very likely to be correlated with increasing levels of lead (β (95% CI): 0.53 (0.99–5.14), p  = 0.023) and cadmium (β (95% CI): 0.43 (0.14–0.73), p  = 0.003) in their hair. In conclusion, children exposed to SHS have increased lead and cadmium accumulations in the body. Conclusion : In our study, 821 students (433 boys and 388 girls) were recruited, and the contents of heavy metals in their hair—including chromium, manganese, nickel, arsenic, lead, and cadmium—were detected by ICP-MS. And the secondhand smoking (SHS) exposure was inquired by face-to-face investigation of their parents. We illustrated that children exposed to SHS have increased lead and cadmium accumulations in the body. What is Known: • Secondhand smoke (SHS) has adverse effects on health, particularly for children. • There might be correlation between SHS exposure and heavy metal concentrations in children . What is New: • The levels of chromium, nickel, arsenic, and lead in girls were significantly higher than in boys . • SHS exposure in children was correlated with increasing levels of lead and cadmium in their hair because of exposure to SHS .