Smoking alters the relationship between maternal zinc intake and biochemical indices of fetal zinc status.

Maternal smoking impairs fetal zinc status. This study was designed to clarify the effect of smoking on the relationship between maternal zinc intake and zinc status in mother and fetus. Zinc was measured with atomic-absorption spectroscopy. Statistical analyses consisted of descriptive statistics, simple correlations, and stepwise multiple regression. The results suggest that maternal plasma zinc, red blood cell zinc, and alkaline phosphatase at term are not related to maternal zinc intake. In the nonsmoking parturient both cord-vein plasma zinc and cord-vein alkaline phosphatase activity are positively related to maternal zinc intake. In the smoking parturient there is no relationship between maternal zinc intake and fetal zinc status except for a negative relation with cord-vein plasma zinc. Relations between maternal zinc intake and placental zinc can be shown with stepwise-multiple-regression techniques. The data suggests that maternal zinc intake is related not to maternal zinc status but to fetal zinc status in a normal pregnancy. The relation is altered in the pregnancy complicated by smoking.

Necrotizing enterocolitis: feeding in endemic and epidemic periods.

Aggressive feeding practices are thought to increase the incidence of necrotizing enterocolitis (NEC). Detailed feeding histories of the 39 cases occurring between January 1, 1984 and May 31, 1985 were compared with matched controls. The study period included a cluster (epidemic) of 11 cases diagnosed within 1 month. Data were analyzed collectively and separately for endemic and epidemic cases. Collectively, cases had greater average daily intake volume, maximum daily intake volume, intake volume on the day prior to diagnosis, and maximum daily caloric intake (all p less than 0.05) than controls. The only recorded parameter that differed in endemic cases vs controls was intake the day prior to diagnosis. In contrast, epidemic cases were fed significantly more volume, more calories, and faster than controls: average intake volume (62.5 +/- 27.2 vs 37.4 +/- 18.0 ml/kg/day); maximum intake volume (118.5 +/- 33.5 vs 76.4 +/- 38.8 ml/kg/day); intake day prior to diagnosis (109.8 +/- 30.9 vs 63.8 +/- 43.1 ml/kg/day); maximum daily increment (42.6 +/- 16.7 vs 26.7 +/- 16.4 ml/kg); maximum caloric intake (126.1 +/- 44.6 vs 77.3 +/- 50.0) (all p less than 0.01). Five of the feeding parameters were significantly less for the epidemic controls than the endemic controls, suggesting a general slowing of feeding during the NEC epidemic. In summary, the data suggest feeding patterns may have an impact on NEC especially during epidemic periods.

The effect of smoking on placental and fetal zinc status.

Previous studies have reported a cadmium/zinc interaction in cadmium-exposed pregnant animals that results in (1) increased placental cadmium levels, (2) increased placental zinc levels, and (3) decreased placental zinc transport. This study was carried out to determine whether zinc status would be affected in pregnant women exposed to cadmium through cigarette smoke. Atomic absorption spectroscopy was used to determine the levels of cadmium and zinc; 65 pregnant women who smoke and 84 who do not smoke were studied. Our data reveal that increased cadmium levels in pregnant women as the result of smoking increase placental zinc levels and decrease cord red blood cell zinc levels. Significantly higher levels of both cadmium and zinc were found in the placentas of pregnant women who smoke; moreover, stepwise multiple regression showed that maternal whole blood cadmium levels predicted placental zinc levels. In regard to cord blood, a significant 9% decrease in the red blood cell zinc level was observed in infants of mothers who smoke and this decrease was correlated with smoking activity, as evaluated by measuring plasma levels of thiocyanate. Also cord red blood cell zinc levels were found to correlate with placental zinc levels in nonsmokers but not in smokers. Overall, our data show that a cadmium/zinc interaction does take place in the maternal-fetal-placental unit of pregnant women who smoke and results in less favorable zinc status in the infants.