Breast feeding and the sudden infant death syndrome in Scandinavia, 1992-95.

AIMS: To assess the effects of breast feeding habits on sudden infant death syndrome (SIDS). METHODS: The analyses are based on data from the Nordic Epidemiological SIDS Study, a case-control study in which parents of SIDS victims in the Scandinavian countries between 1 September 1992 and 31 August 1995 were invited to participate, each with parents of four matched controls. The odds ratios presented were computed by conditional logistic regression analysis. RESULTS: After adjustment for smoking during pregnancy, paternal employment, sleeping position, and age of the infant, the adjusted odds ratio (95% CI) was 5.1 (2.3 to 11.2) if the infant was exclusively breast fed for less than four weeks, 3.7 (1.6 to 8.4) for 4-7 weeks, 1.6 (0.7 to 3.6) for 8-11 weeks, and 2.8 (1.2 to 6.8) for 12-15 weeks, with exclusive breast feeding over 16 weeks as the reference. Mixed feeding in the first week post partum did not increase the risk. CONCLUSIONS: The study is supportive of a weak relation between breast feeding and SIDS reduction.     

Prenatal exposure to Chernobyl fallout in Norway: neurological and developmental outcomes in a 25-year follow-up

Ionizing radiation at high doses early in life may cause neurodevelopmental problems. Possible effects of lower doses are, however, controversial. We use carefully collected exposure data for Norway following the Chernobyl accident in April 1986 combined with population-based registries to assess long-term effects of fetal exposure on neurodevelopmental outcomes. Radiation doses were estimated for each Norwegian municipality for each calendar month from May 1986 to April 1989. We established a cohort of all Norwegian pregnancies during the three-year period of radiation measurement and compared them with appropriate unexposed groups. All cohorts were followed into adulthood. Risks of cerebral palsy, mental retardation, schizophrenia, epilepsy, vision or hearing problems, school dropout, and low income were estimated. We also conducted an analysis of mathematics and language grades using siblings born after the exposure period as comparison. There was little evidence of associations between radiation exposure and cerebral palsy, mental retardation, schizophrenia, epilepsy, or hearing or vision problems associated with radiation exposure. (p-values for trend with exposure dose were 0.27, 0.14, 0.83, 0.35 and 0.42.) Slightly more of the exposed failed to complete high school (p = 0.05), but there was no increase in the proportion with low income (p = 0.38). The natural advantage of older siblings over younger siblings in mathematics grades was diminished with exposure of older siblings (p = 0.003), but there was no association of exposure with Norwegian language grades (p = 0.37). There is scant evidence that the low-dose fallout from Chernobyl in Norway increased the risk for serious neurodevelopmental problems. We cannot exclude the possibility of lower mathematics grades with exposure, similar to a report from Sweden.     

Eye discomfort, headache and back pain among Mayan Guatemalan women taking part in a randomised stove intervention trial

BACKGROUND: Indoor air pollution (IAP) from combustion of biomass fuels represents a global health problem, estimated to cause 1.6 million premature deaths annually. AIMS: RESPIRE (Randomised Exposure Study of Pollution Indoors and Respiratory Effects) Guatemala is the first randomised controlled trial ever performed on health effects from solid fuel use. Its goal is to assess the effect of improved stoves (planchas) on exposure and health outcomes in a rural population reliant on wood fuel. METHODS: Questions about symptoms were asked at baseline and periodically after the intervention, to an initial group of 504 women (259 randomly assigned to planchas (mean (standard deviation) age 27.4 (7.2) years) and 245 using traditional open fires (28.1 (7.1) years)). Levels of carbon monoxide (CO) in exhaled breath, a biomarker of recent exposure to air pollution from biomass combustion, were measured at each visit. In addition to reducing IAP levels, the plancha may also have a positive health effect by changing the working posture to an upright position. RESULTS: A high prevalence of eye discomfort, headache and backache was found. The odds of having sore eyes and headache were substantially reduced in the plancha group relative to the group using open fires for the follow-up period (odds ratio (OR) 0.18, 95% confidence interval (CI) 0.11 to 0.29 and (OR) 0.63, 95% CI 0.42 to 0.94, respectively). Median CO in breath among women in the intervention trial was significantly lower than controls. CONCLUSION: In addition to reducing discomfort for women, tangible improvements in symptoms experienced by a substantial proportion of women may help to gain acceptance and wider use of planchas.     

Rapid genotyping of the human renin (REN) gene by the LightCycler® instrument: identification of unexpected nucleotide substitutions within the selected hybridization probe area

Preeclampsia is a serious disorder affecting nearly 3% of all in the Western world. It is associated with hypertension and proteinuria, and several lines of evidence suggest that the renin-angiotensin system (RAS) may be involved in the development of hypertension at different stages of a preeclamptic pregnancy. In this study, we developed rapid genotyping assays on the LightCycler® instrument to allow the detection of genetic variants in the renin gene (REN) that may predispose to preeclampsia. The method is based on real-time PCR and allele-specific hybridization probes, followed by fluorescent melting curve analysis to expose a change in melting temperature (T_m). Ninety-two mother-father-child triads (n=276) from preeclamptic pregnancies were genotyped for three haplotype-tagging single nucleotide polymorphisms (htSNPs) in REN. All three htSNPs (rs5705, rs1464816 and rs3795575) were successfully genotyped. Furthermore, two unexpected nucleotide substitutions (rs11571084 and rs61757041) were identified within the selected hybridization probe area of rs1464816 and rs3795575 due to aberrant melting peaks. In conclusion, genotyping on the LightCycler® instrument proved to be rapid and highly reproducible. The ability to uncover additional nucleotide substitutions is particularly important in that it allows the identification of potentially etiological variants that might otherwise be overlooked by other genotyping methods.     

Increasing risk of gastroschisis in Norway: an age-period-cohort analysis

The prevalence of gastroschisis in Norway, as reported to the Medical Birth Registry of Norway, increased regularly and sixfold from 0.5 to 2.9 per 10,000 births during 1967-1998. The prevalence was also consistently higher among children of younger mothers. The authors used age-period-cohort analysis to assess effects of both parents' age and year of birth (parental cohorts). Mother's and father's age were included in three different regression models. Apart from a significantly higher risk at a young maternal age, the authors also found higher risk at a young paternal age (1.6-fold per 10 years' reduction in father's age, 95% confidence interval: 1.0, 2.4). The time trend was highly significant regardless of whether it was ascribed to period, mother's year of birth, or father's year of birth. However, when father's year of birth was used to describe the time trend, no apparent additional effect of father's age was found, only for mother's age. The time trend is likely caused by environmental factors. Persistently increasing risks among children of young mothers may hypothetically be related to lifestyle factors. A contribution to risk also from fathers born in more recent years or from young fathers increases the likelihood that a factor related to modern lifestyles of young couples may be related to risk.