Tobacco Use Increases Oxidative DNA Damage in Sperm - Possible Etiology of Childhood Cancer


Background: Cigarette smoking and tobacco chewing are common modes of consuming tobacco all overthe world. Parents need to be aware that germ cell integrity is vital for birth of healthy offspring as biologicalparenting begins much before birth of a child and even before conception. The present study was conducted todetermine the etiology of non-familial sporadic heritable retinoblastoma (NFSHRb), by evaluating oxidativesperm DNA damage in fathers due to use of tobacco (smoking and chewing). Materials and
Methods: We recruited145 fathers of NFSHRb children and 53 fathers of healthy children (controls) in the study. Tobacco history wasobtained by personal interview. Seminal reactive oxygen species (ROS) in semen, sperm DNA fragmentationindex (DFI) and 8 hydroxy 2’ deoxyguanosine (8-OHdG) levels in sperm were evaluated. The RB1 gene wasscreened in genomic blood DNA of parents of children with NFSHRb and controls. Odds ratios (ORs) derivedfrom conditional logistic regression models.
Results: There was significant difference in the levels of ROS (p<0.05),DFI (p<0.05) and 8-OHdG (p<0.05) between tobacco users and non-users. The OR of NFSHRb for smokers was7.29 (95%CI 2.9-34.5, p<0.01), for tobacco chewers 4.75 (2.07-10.9, p<0.05) and for both 9.11 (3.79-39.2; p<0.01).
Conclusions: This study emphasizes the adverse effect of tobacco on the paternal genome and how accumulationof oxidative damage in sperm DNA may contribute to the etiology of NFSHRb. In an ongoing parallel study inour laboratory, 11 of fathers who smoked underwent. Meditation and yoga interventions, showed significantdecline in levels of highly mutagenic oxidised DNA adducts after 6 months. Thus our lifestyle and social habitsimpact sperm DNA integrity and simple interventions like yoga and meditation are therapeutic for oxidativedamage to sperm DNA.