Paternal occupation and neural tube defects: a case-control study based on the Oxford Record Linkage Study register.

Certain paternal occupations and related exposures have been suggested as possible risk factors for neural tube defects (NTD). We analysed data collected as part of a case-control study to investigate the relationship between paternal occupational exposures and NTD. Cases were 694 NTD-affected pregnancies diagnosed between 1970 and 1987 in Oxfordshire or West Berkshire, England. Controls were randomly selected from a computerised maternity database individually matched to cases on maternal year of birth and year of index pregnancy. Data on paternal occupation were abstracted from hospital antenatal records. Associations between paternal occupational exposures and NTD were assessed using odds ratios adjusted for maternal year of birth, year of index pregnancy, gender of baby, multiplicity of birth and number of previous obstetric events. Statistically significant positive associations were observed for paternal occupational exposure to agrochemicals and animals. Analysis by occupational title revealed that more case than control fathers were farmers, gardeners and butchers. Statistically significant negative associations were seen for paternal occupational exposure to inhaled hydrocarbons and metal-working oil mists. The findings from this population-based study for paternal agricultural and animal-related occupations overlap and have been previously observed. The apparent protective effects of fathers working with inhaled hydrocarbons and metal-working oil mists have not been previously described. No underlying biological mechanisms have been identified, therefore other explanations cannot be excluded.

Pregnancy outcome among twins conceived after subfertility treatment compared with natural twins: A population-based study.

Pregnancy outcome and characteristics of women who conceive following subfertility treatment remains a subject of great interest. We analyzed these variables among 199 women who delivered a registerable twin birth compared with 1773 women who delivered a naturally conceived twin birth in a population-based obstetric cohort drawn from around Oxford, England. Treatment was restricted to conceptions involving simple ovulation induction only. Treated mothers were of significantly higher social class and older, more likely to deliver girls and to be delivered by cesarean section, and significantly less likely to be smokers at the time of antenatal booking and to have delivered previous pregnancies. Pregnancy outcome was similar between the two groups for most measures, with the exception of birthweight which was lower in treated twins, though not significantly so. Overall the results are reassuring with respect to outcome in twin pregnancies following simple ovulation induction.

Does smoking influence survival in cancer patients through effects on respiratory and vascular disease?

Patients with cancers caused by smoking may die because they continue to smoke even after diagnosis of a cancer caused by smoking. We investigated differences in cause-specific mortality between patients diagnosed with smoking-related and non-smoking-related cancers. The causes of death were classified as smoking-related cancer, non-smoking-related cancer, respiratory or vascular disease, and all other causes. We studied all 220 089 people diagnosed with cancer in Scotland between 1986 and 1996, aged between 20 and 85 years, with last follow-up on 31 December 1999. There was a moderate excess risk of dying from respiratory and vascular causes in those with smoking-related cancers, which did not fall with time since diagnosis, consistent with continued smoking by these patients. Mortality among cancer patients might fall if more assistance in stopping smoking was provided for patients who have smoking-related cancers.

Zyban for smoking cessation in a general practice setting: the response to an invitation to make a quit attempt.

The objective of this study was to assess the feasibility and success of Zyban as part of a moderately supported smoking cessation programme within UK general practice. Treatment was offered to 479 moderately dependent smokers (smoking 15 or more cigarettes per day) who had never used Zyban, and who had taken part in a previous NRT trial (the PATCH study). Main outcome measures were point prevalence and continuous abstinence from smoking at 6 and at 12 months. Two hundred and forty were excluded because of medical reasons or prescribing contraindication. Of the remainder (n=239) only 54 (23%) made an active quit attempt. Thirty percent (16/54) were abstinent at six months, and 22% (12/54) at 12 months (biochemically validated point prevalence rates). Age, socio-economic status, nicotine dependence, and genetic profile appeared to have little impact on success rates, but male quit-attempters were significantly more successful than female (40% vs. 10% at 12 months, p<0.05). In conclusion, a real-world smoking cessation programme using Zyban with moderate support within a general practice setting may achieve satisfactory quit rates without widening existing disparities in cessation.

Genetic variation in dopaminergic pathways and short-term effectiveness of the nicotine patch.

Polymorphisms in the dopamine D2 receptor (DRD2 C/T and DRD2 A/G) and in dopamine beta hydroxylase (DBH A/G) have been implicated in modulation of smoking and other reward-seeking behaviours. We hypothesized that these alleles would predict the outcome of nicotine patch therapy for smoking cessation. In 1991-93, we performed a randomized controlled trial of the nicotine patch on 1686 heavy smokers (> or = 15 cigarettes/day). In 1999-2000, we contacted 1532 of the 1612 subjects still available; 767 (50%) completed a questionnaire and gave a blood sample. In the 755 cases in which DNA was successfully genotyped, we examined associations between the polymorphisms in DRD2 and DBH, and smoking cessation. At 1 week, the patch was more effective for smokers with DRD2 CT/TT genotype [patch/placebo odds ratio (OR) 2.8, 95% confidence interval (CI) 1.7-4.6] than with CC (OR 1.4, 0.9-2.1; P for difference in ORs 0.04). Smokers with both DRD2 CT/TT and DBH GA/AA genotypes had an OR of 3.6 (2.0-6.5) compared to 1.4 (1.0-2.1) for others (P = 0.01). At 12 weeks, the ORs for these genotypic groups were 3.6 (1.7-7.8) and 1.4 (0.9-2.3), respectively (P = 0.04). There was no association between patch effectiveness and DRD2 exon 8. Short-term effectiveness of the nicotine patch may be related to dopamine beta-hydroxylase and dopamine D2 receptor genotype. Our results support the need for further investigation into personalized therapies for smoking cessation based on individual genotype.

Does cigarette smoking increase time to conception?

Data are reported on the relationship between cigarette smoking and other health-related behaviours and time to conception in a population-based sample of women who acted as a control group in a case-control study of twinning. Women who continued to smoke close to the time of conception took significantly longer to become pregnant than women who never smoked or stopped smoking before the year during which they attempted to conceive. A hierarchical regression analysis performed on time-to-conception data in women who continued to smoke in the year before conception provided weak evidence for a dose-response relationship between time to conception and number of cigarettes smoked per day. No significant relationships were found between time to conception and other health-related behaviours.