Sperm count half lower in sons of smok­ing fa­thers

Weekly Trust - - Weekend Health - Judd-Leonard Okafor, with agency re­port

Smok­ing in men may re­duce your testos­terone lev­els, but it may also re­duce the sperm count of your sons, ac­cord­ing to a new study at Swe­den’s Lund Uni­ver­sity pub­lished on PlosOne.

Pre­vi­ous stud­ies have re­peat­edly linked re­duced sperm counts in males to smok­ing by women dur­ing preg­nancy.

The new study shows sons of fa­thers who smoked at the time of preg­nancy had half as many sperm as those with non­smok­ing fa­thers.

The study was con­ducted on 104 Swedish men aged be­tween 17 and 20.

Once the re­searchers had ad­justed for the mother’s own ex­po­sure to nico­tine, so­cioe­co­nomic fac­tors, and the sons’ own smok­ing, men with fa­thers who smoked had a 41 per cent lower sperm con­cen­tra­tion and 51 per cent fewer sperm than men with non-smok­ing fa­thers.

“I was very sur­prised that, re­gard­less of the mother’s level of ex­po­sure to nico­tine, the sperm count of the men whose fa­thers smoked was so much lower”, says Jonatan Ax­els­son, spe­cial­ist physi­cian in oc­cu­pa­tional and en­vi­ron­men­tal medicine.

“Un­like the ma­ter­nal ovum, the fa­ther’s ga­metes di­vide con­tin­u­ously through­out life and mu­ta­tions of­ten oc­cur at the pre­cise mo­ment of cell di­vi­sion. We know that to­bacco smoke con­tains many sub­stances that cause mu­ta­tions so one can imag­ine that, at the time of con­cep­tion, the ga­metes have un­der­gone mu­ta­tions and thereby pass on genes that re­sult in re­duced sperm qual­ity in the male off­spring.”

Most newly oc­cur­ring mu­ta­tions come via the fa­ther and there are also links be­tween the fa­ther’s age and a num­ber of com­plex dis­eases.

In ad­di­tion, re­searchers have ob­served that smok­ing is linked to DNA dam­age in sperm and that smok­ers have more breaks in the DNA strand.

Chil­dren of fa­thers who smoke have been re­ported to have up to four times as many mu­ta­tions in a cer­tain repet­i­tive part of the DNA as chil­dren of non-smok­ing fa­thers.

“We know there is a link be­tween sperm count and chances of preg­nancy, so that could af­fect the pos­si­bil­ity for these men to have chil­dren in fu­ture. The fa­ther’s smok­ing is also linked to a shorter re­pro­duc­tive life­span in daugh­ters, so the no­tion that ev­ery­thing de­pends on whether the mother smokes or not doesn’t seem con­vinc­ing. Fu­ture re­search could per­haps move us closer to a causal link,” con­cludes Ax­els­son.

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