type II. Prospective comparative study.

The relationship between migraine and blood pressure is controversial. We studied the association between migraine and blood pressure in a population-based sample of elderly patients. Participants were 1373 subjects 59-71 years of age. Lifetime migraine was diagnosed according to the International Headache Society criteria by a headache specialist. Blood pressure was measured as well as the carotid intima-media thickness (IMT) which is a good marker of the long-term exposure to high blood pressure. Migraine during life was diagnosed in 140 participants. Mean systolic blood pressure was lower in subjects with migraine than in those without headache (128 mmHg vs. 137 mmHg). There was a significant trend of decreasing frequency of migraine with increasing blood pressure and also with increasing IMT. In this study, migraine was associated with lower levels of blood pressure and with smaller values of carotid wall thickness.

Although prenatal exposure to water disinfection by-products does not appear to affect the duration of gestation, its impact on fetal growth remains an open question. The authors studied the associations between prenatal exposure to disinfection by-products and fetal growth restriction (FGR) and preterm birth in the PELAGIE cohort, a French birth cohort comprising 3,421 pregnant women recruited between 2002 and 2006. Exposure was assessed by estimating levels of trihalomethanes (THMs) in tap water during pregnancy and maternal water use and by measuring maternal urinary levels of trichloroacetic acid (TCAA) during early pregnancy in a nested case-control design that compared 174 FGR cases, 114 preterm births, and 399 controls. Higher uptake of THMs (especially brominated THMs) was associated with a higher risk of FGR. Women with TCAA detected in their urine (>0.01 mg/L) had a higher risk of FGR than those with TCAA levels below the detection limit (adjusted odds ratio = 1.8, 95% confidence interval: 0.9, 3.7) and had an odds ratio for preterm birth below 1 (adjusted odds ratio = 0.8, 95% confidence interval: 0.3, 2.6). Results from this prospective study, the first to use a biomarker of disinfection by-product exposure, suggest that prenatal exposure affects fetal growth, but the causal agent or agents remain to be identified.

Diagnostic study, Level I.

No abstract