The results of the study is given in the article. Are there alternate explanations for the results?
In the article Association of Arsenic Exposure during Pregnancy with Fetal Loss and Infant Death. A cohort study in Bangladesh.
The study of Rahman et al., evaluated the effect of arsenic exposure, through consumption of contaminated tube well water, on infant death and fetal loss in Matlab, Bangladesh. The authors report a strong correlation between the arsenic concentration in tube well water and the outcomes. There could be potential alternate explanations for some of this correlation:
- Malnutrition: The study did not account for malnutrition, which could be a big factor in infant death and fetal loss.
- Healthcare: It has been assumed that all the subjects received adequate healthcare, which may not be true in at least some of the cases. Lack of adequate and timely healthcare could have increased the number of losses.
- History of fetal loss and infant death: The study did not incorporate any history of fetal loss and infant death for each subject. If a subject has had a history of such instances, they may be more likely to have a repeat incident.
- Variations in arsenic concentration: The pregnancy history of 1991-2000 was used, while the arsenic concentrations were measured later (2002-2003). There is no evidence that the same concentration of arsenic existed during the pregnancy. The concentration could have been more or less, thus the results of correlation with concentration greater than 50 ppb could be erroneous.
There could be a number of alternate explanations (apart from the ones presented above) for at least some of the cases and hence the results could have been improved, through a better study design. The authors could have discussed some of these factors or alternate explanations, in the article.
Hope this helps.