Water composition in the etiology of anencephalus.

This case-control study was based on 468 deaths from anencephalus and a random sample of 4129 livebirths occurring during 1969 to 1972 to mothers resident in 142 localities of over 10,000 population in Canada. Anencephalus risk was associated with the previous pregnancy history of the mother, with legitimacy, year of birth and with the longitude of the mother's residence, but after adjusting for these there was no significant association seen with locality population size, mean income, the proportion of women employed, latitude, or with the concentrations in drinking water of any of 14 elements: calcium, magnesium, copper, lithium, zinc, nickle, lead, selenium, mercury, chromium, silver, cobalt, cadmium and molybdenum.