Interaction of maternal protein and carbon monoxide on pup mortality in mice: implications for global infant mortality.
BACKGROUND
The United States Surgeon General declared 2005 as the "Year of Healthy Child." To improve the health of all children, we need to start before pregnancy, with their mothers. Unfortunately, protein deficiency in the diets of poor pregnant mothers in developing countries is widespread. Carbon monoxide (CO) pollution is serious public health problem in developed and developing countries.


METHODS
A two-way factorial experimental design was used. Mice were maintained on 27%, 16%, 8%, or 4% protein diets. Dams were exposed to 0 ppm (control), 65 ppm, or 125 ppm CO in air, in environmental chambers for 6 hr/day during the first 2 weeks of pregnancy. Controls were also subjected to environmental chamber conditions. Food and water were available at all times. Animals were allowed to deliver, and data on pup mortality was recorded.


RESULTS
Litter size was not affected by CO exposure, but was directly related to the dietary protein levels. Pup weight was inversely related to the CO exposure level, and directly related to the dietary protein levels. Pup mortality on date of birth was increased by CO exposure and was inversely related to the dietary protein levels. Pup mortality at 1 week of age was increased by CO exposure and 55% of all pups died in 125 ppm CO exposed group. Pup mortality at 1 week of age was inversely related to dietary protein levels. All pups in the 4% dietary protein and in all concentrations of CO died. All pups in the 8% protein group and in all CO concentrations died except in 125 ppm CO group. Pup mortality in the 16% dietary protein group ranged from 14.8% in 0 ppm to 36.8% in 65 ppm CO groups. Pup mortality in the 27% dietary protein group ranged from 14.3% in the 0 ppm to 41.1% in the 125 ppm CO groups.


CONCLUSIONS
DATA suggest that protein deficiency and CO exposure enhance pup mortality. The protein and CO also interact to increase pup mortality in 16% and 27% protein groups. Carbon monoxide exposure, along with protein deficiency during gestation, may be contributing factors for high rates of infant mortality in developing countries. The results of the study also suggest that un-vented combustion for heating and cooking, ambient pollution, and biomass smoke may have a major impact on the health of children worldwide; and may explain the causes of high infant mortality in poor countries and some sections of the United States population.
Singh
Jarnail
J
Stillman College, Tuscaloosa, Alabama 35403, USA. jsingh@stillman.edu
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001724:Birth Weight / Q000187:drug effects; D002248:Carbon Monoxide / Q000633:toxicity*; D004044:Dietary Proteins / Q000494:pharmacology*; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D008098:Litter Size / Q000187:drug effects; D051379:Mice; D011247:Pregnancy; D015996:Survival Rate; D015430:Weight Gain / Q000187:drug effects
D004044:Dietary Proteins; D002248:Carbon Monoxide