Alexandra Farrow

Delayed conception and active and passive smoking

OBJECTIVE To determine whether passive as well as active smoking by women or smoking by men is associated with delayed conception, after adjustment for confounding factors. DESIGN Population study of couples expecting a baby. Logistic regression was performed to identify factors associated with delayed conception. SETTING The Avon Health Authority area, United Kingdom. PATIENT(S) All couples expected to deliver between April 1991 and December 1992. INTERVENTION(S) Questionnaires administered early in pregnancy. MAIN OUTCOME MEASURE(S) Time taken to conceive, categorized as <6 months, 6-11 months, 1-3 years, and >3 years. RESULT(S) After correction for confounding factors, delayed conception was statistically significantly associated with both active smoking by the woman (odds ratio [OR] 1.23 [95% CI 0.98-1.49] for > 6 months and 1.54 [95% CI 1.19-2.01] for >12 months) and her exposure to passive smoking (OR 1.17 [95% CI 1.02-1.37] and 1.14 [95% CI 0.92-1.42]) compared with women with no exposure to tobacco smoke (referent). Heavy smoking by men was independently associated with delayed conception. In active smokers, the effect increased with the number of cigarettes. CONCLUSION(S) Smoking by men and passive and active smoking by women are associated with delayed conception.

Frequent use of chemical household products is associated with persistent wheezing in pre-school age children

Background: In the UK and other developed countries the prevalence of asthma symptoms has increased in recent years. This is likely to be the result of increased exposure to environmental factors. A study was undertaken to investigate the association between maternal use of chemical based products in the prenatal period and patterns of wheeze in early childhood. Methods: In the population based Avon Longitudinal Study of Parents and Children (ALSPAC), the frequency of use of 11 chemical based domestic products was determined from questionnaires completed by women during pregnancy and a total chemical burden (TCB) score was derived. Four mutually exclusive wheezing patterns were defined for the period from birth to 42 months based on parental questionnaire responses (never wheezed, transient early wheeze, persistent wheeze, and late onset wheeze). Multinomial logistic regression models were used to assess the relationship between these wheezing outcomes and TCB exposure while accounting for numerous potential confounding variables. Complete data for analysis was available for 7019 of 13 971 (50%) children. Results: The mean (SD) TCB score was 9.4 (4.1), range 0–30. Increased use of domestic chemical based products was associated with persistent wheezing during early childhood (adjusted odds ratio (OR) per unit increase of TCB 1.06 (95% confidence interval (CI) 1.03 to 1.09)) but not with transient early wheeze or late onset wheeze. Children whose mothers had high TCB scores (>90th centile) were more than twice as likely to wheeze persistently throughout early childhood than children whose mothers had a low TCB score (<10th centile) (adjusted OR 2.3 (95% CI 1.2 to 4.4)). Conclusion: These findings suggest that frequent use of chemical based products in the prenatal period is associated with persistent wheezing in young children. Follow up of this cohort is underway to determine whether TCB is associated with wheezing, asthma, and atopy at later stages in childhood.

Household chemicals, persistent wheezing and lung function: effect modification by atopy?

The aims of the present study were to assess the effects of maternal use of domestic chemicals during pregnancy on wheezing and lung function in children aged ≤8.5 yrs and to explore the potential modifying effect of atopy. In the Avon Longitudinal Study of Parents and Children, a cohort study, a maternal composite household chemical exposure (CHCE) score was derived. Wheezing phenotypes from birth to age 7 yrs were assigned on the basis of reported wheeze. Lung function (forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced midexpiratory flow between 25 and 75% of FVC (FEF25–75%)) was measured at age 8.5 yrs; and atopy by skin-prick tests at age 7.5 yrs. Multinomial logistic and linear regression models assessed the relationship between wheezing outcomes, lung function and CHCE score, and interactions with atopy. Increased CHCE score was associated with early- (<18 months) and intermediate- (18–30 months) persistent and late-onset (>30 months) wheezing in nonatopic children (adjusted odds ratio per z-score of CHCE (95% confidence interval) 1.41 (1.13–1.76), 1.43 (1.02–2.13) and 1.69 (1.19–2.41), respectively). Increasing CHCE score was associated with decrements in FEV1 and FEF25–75%. Higher domestic chemical exposure during pregnancy was associated with persistent wheeze and lung function abnormalities in nonatopic children. This may result from pre-natal developmental effects or post-natal irritant effects on the developing airway, but is unlikely to be mediated through increased hygiene in the home.

Time Spent in the Home by Different Family Members

The study objective was to assess the length of time spent inside the home for each family member in a sample population in the southwest of England. Such information is vital in any study concerned with exposure to pollutants in the home environment, in order to calculate a dose response for a specific health effect in the individual. The design was a longitudinal observational study which started in pregnancy and was carried out for one week in each month over a 12 month period. The setting was a sample of 170 families within the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC) where indoor air pollutants were being measured. The number of hours spent in the home each day for each family member was obtained from self-report using weekly diary sheets‥ The results indicated that mothers, fathers and young infants spent an average of 18.4 (76.7%), 14.7 (61.3%) and 19.3 (80.4%) hours per day, respectively, in the home. In winter, infants spent longer in the home than in the summer months. At week...

Dependence of Deodorant Usage on ABCC11 Genotype: Scope for Personalized Genetics in Personal Hygiene

Earwax type and axillary odor are genetically determined by rs17822931, a single-nucleotide polymorphism (SNP) located in the ABCC11 gene. The literature has been concerned with the Mendelian trait of earwax, although axillary odor is also Mendelian. Ethnic diversity in rs17822931 exists, with higher frequency of allele A in east Asians. Influence on deodorant usage has not been investigated. In this work, we present a detailed analysis of the rs17822931 effect on deodorant usage in a large (N∼17,000 individuals) population cohort (the Avon Longitudinal Study of Parents and Children (ALSPAC)). We found strong evidence (P=3.7 × 10−20) indicating differential deodorant usage according to the rs17822931 genotype. AA homozygotes were almost 5-fold overrepresented in categories of never using deodorant or using it infrequently. However, 77.8% of white European genotypically nonodorous individuals still used deodorant, and 4.7% genotypically odorous individuals did not. We provide evidence of a behavioral effect associated with rs17822931. This effect has a biological basis that can result in a change in the familys environment if an aerosol deodorant is used. It also indicates potential cost saving to the nonodorous and scope for personalized genetics usage in personal hygiene choices, with consequent reduction of inappropriate chemical exposures for some.

Nitrogen dioxide in infants' bedrooms : a feasibility study for household based measurements

To determine the feasibility of postal methods to measure indoor and outdoor levels of nitrogen dioxide without technical intervention of trained staff. Postal distribution of Palmes diffusion tubes to the householder to measure nitrogen dioxide levels inside the babys bedroom and outside homes followed by a questionnaire ascertaining possible sources of nitrogen dioxide. Setting: Three health districts in Avon during two weeks in November 1992; 100 women, randomly selected from those with infants 4–6 months of age, currently participating in the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC). Outcome measures: Response rate and evidence of understanding and implementation of the method by the householder; the comparability of results to those obtained from studies using visits by trained staff, for ratios of nitrogen dioxide outdoors/indoors and in homes with and without a gas cooker. There was a 91% response rate with all but one family carrying out the measurements successfully. The ratio...