No abstract

The decline in the prevalence of spina bifida was temporally associated with folic acid fortification of US grain supplies. The temporal association between fortification and the prevalence of anencephaly is unclear.

Overall, first-year survival for infants with congenital anomalies was high. Additional population-based studies are needed to quantify improvements in first-year survival.

Objective To evaluate the association between preterm birth and major birth defects by maternal and infant characteristics and specific types of birth defects. Study Design We pooled data for 1995-2000 from 13 states with population-based birth defects surveillance systems, representing about 30% of all U.S. births. Analyses were limited to singleton, live births from 24-44 weeks gestational age. Results Overall, birth defects were more than twice as common among preterm births (24-36 weeks) compared with term births (37-41 weeks gestation) (prevalence ratio [PR] = 2.65, 95% confidence interval [CI] 2.62-2.68), and approximately 8% of preterm births had a birth defect. Birth defects were over five times more likely among very preterm births (24-31 weeks gestation) compared with term births (PR = 5.25, 95% CI 5.15-5.35), with about 16% of very preterm births having a birth defect. Defects most strongly associated with very preterm birth included central nervous system defects (PR = 16.23, 95% CI 15.49-17.00) and cardiovascular defects (PR = 9.29, 95% CI 9.03-9.56). Conclusions Birth defects contribute to the occurrence of preterm birth. Research to identify shared causal pathways and risk factors could suggest appropriate interventions to reduce both preterm birth and birth defects.

Recent research has suggested that nonionizing radiation in the form of power-frequency magnetic fields may play some role in carcinogenesis in general and in acute nonlymphocytic leukemia in particular. Much of the epidemiologic evidence is preliminary in nature and the methods of previous studies have been criticized. In order to further evaluate this hypothesis, a population-based case-control study of adult acute nonlymphocytic leukemia and residential exposure to power-frequency magnetic fields was carried out in western Washington state. Analyses were based on 114 cases who were newly diagnosed from 1981 to 1984 and identified from a population-based cancer registry, and 133 controls who were chosen from the study area by random digit dialing. Magnetic field exposure was estimated from external electrical wiring configurations within 140 ft (42.7 m) of each subject's residence. In addition, magnetic fields were measured inside the subject's residence at the time of interview. Neither the directly measured magnetic fields nor the surrogate values based on the wiring configurations were associated with acute nonlymphocytic leukemia.

Our study confirmed findings in previous studies, but also uncovered several new associations.

No abstract

Wildlife studies suggest that consumption of contaminated fish from the Great Lakes may expose humans to polychlorinated biphenyls and persistent chlorinated pesticides. To assess whether time to pregnancy or fecundability is affected, we conducted a telephone survey in 1993 with female members of the New York State Angler Cohort Study who were considering pregnancy between 1991 and 1994 (N = 2,445). Among the 1,234 (50%) women who became pregnant, 895 (73%) had a known time to pregnancy. Upon enrollment into the cohort in 1991, both partners reported duration and frequency of Lake Ontario sport fish consumption. We estimated lifetime exposure to polychlorinated biphenyls from recent consumption and used a discrete-time analog of Cox proportional hazards analysis to estimate conditional fecundability ratios and 95% confidence intervals (CIs) for fish consumption among couples with complete exposure data who discontinued birth control to become pregnant (N = 575). Maternal consumption of fish for 3-6 years was associated with reduced fecundability (fecundability ratio = 0.75; 95% CI = 0.59-0.91), as was more than a monthly fish meal in 1991 (fecundability ratio = 0.73; 95% CI = 0.54-0.98). Our findings suggest that maternal but not paternal consumption of contaminated fish may reduce fecundability among couples attempting pregnancy.