Paternal and maternal ages at conception and risk of bipolar affective disorder in their offspring

Background. A consistent association between paternal age and their offspring`s risk of schizophrenia has been observed, with no independent association with maternal age. The relationship of paternal and maternal ages with risk of bipolar affective disorders (BPAD) in the offspring is less clear. The present study aimed at testing the hypothesis that paternal age is associated with their offspring`s risk of BPAD, whereas maternal age is not. Method. This population-based cohort study was conducted with individuals born in Sweden during 1973-1980 and still resident there at age 16 years. Outcome was first hospital admission with a diagnosis of BPAD. Hazard ratios (HRs) were calculated using Cox`s proportional hazard regression. Results. After adjustment for all potential confounding variables except maternal age, the HR for risk of BPAD for each 10-year increase in paternal age was 1.28 [95% confidence interval (Cl) 1.11-1.48], but this fell to 1.20 (95% CI 0.97-1.48) after adjusting for maternal age. A similar result was found for maternal age and risk of BPAD [HR 1.30 (95% CI 1.08-1.56) before adjustment for paternal age, HR 1.12 (95% Cl 0.86-1.45) after adjustment]. The HR associated with having either parent aged 30 years or over was 1.26 (95% CI 1.01-1.57) and it was 1.45 (95%, CI 1.16-1.81) if both parents were >30 years. Conclusions. Unlike schizophrenia, the risk of BPAD seems to be associated with both paternal and maternal ages.

Sexual behaviours and the risk of head and neck cancers: a pooled analysis in the International Head and Neck Cancer Epidemiology (INHANCE) consortium

Background Sexual contact may be the means by which head and neck cancer patients are exposed to human papillomavirus (HPV). Methods We undertook a pooled analysis of four population-based and four hospital-based case-control studies from the International Head and Neck Cancer Epidemiology (INHANCE) consortium, with participants from Argentina, Australia, Brazil, Canada, Cuba, India, Italy, Spain, Poland, Puerto Rico, Russia and the USA. The study included 5642 head and neck cancer cases and 6069 controls. We calculated odds ratios (ORs) of associations between cancer and specific sexual behaviours, including practice of oral sex, number of lifetime sexual partners and oral sex partners, age at sexual debut, a history of same-sex contact and a history of oral-anal contact. Findings were stratified by sex and disease subsite. Results Cancer of the oropharynx was associated with having a history of six or more lifetime sexual partners [OR = 1.25, 95% confidence interval (CI) 1.01, 1.54] and four or more lifetime oral sex partners (OR = 2.25, 95% CI 1.42, 3.58). Cancer of the tonsil was associated with four or more lifetime oral sex partners (OR = 3.36, 95 % CI 1.32, 8.53), and, among men, with ever having oral sex (OR = 1.59, 95% CI 1.09, 2.33) and with an earlier age at sexual debut (OR = 2.36, 95% CI 1.37, 5.05). Cancer of the base of the tongue was associated with ever having oral sex among women (OR = 4.32, 95% CI 1.06, 17.6), having two sexual partners in comparison with only one (OR = 2.02, 95% CI 1.19, 3.46) and, among men, with a history of same-sex sexual contact (OR = 8.89, 95% CI 2.14, 36.8). Conclusions Sexual behaviours are associated with cancer risk at the head and neck cancer subsites that have previously been associated with HPV infection.

Cessation of alcohol drinking, tobacco smoking and the reversal of head and neck cancer risk

Background Quitting tobacco or alcohol use has been reported to reduce the head and neck cancer risk in previous studies. However, it is unclear how many years must pass following cessation of these habits before the risk is reduced, and whether the risk ultimately declines to the level of never smokers or never drinkers. Methods We pooled individual-level data from case-control studies in the International Head and Neck Cancer Epidemiology Consortium. Data were available from 13 studies on drinking cessation (9167 cases and 12 593 controls), and from 17 studies on smoking cessation (12 040 cases and 16 884 controls). We estimated the effect of quitting smoking and drinking on the risk of head and neck cancer and its subsites, by calculating odds ratios (ORs) using logistic regression models. Results Quitting tobacco smoking for 1-4 years resulted in a head and neck cancer risk reduction [OR 0.70, confidence interval (CI) 0.61-0.81 compared with current smoking], with the risk reduction due to smoking cessation after >= 20 years (OR 0.23, CI 0.18-0.31), reaching the level of never smokers. For alcohol use, a beneficial effect on the risk of head and neck cancer was only observed after >= 20 years of quitting (OR 0.60, CI 0.40-0.89 compared with current drinking), reaching the level of never drinkers. Conclusions Our results support that cessation of tobacco smoking and cessation of alcohol drinking protect against the development of head and neck cancer.