Geospatial association between adverse birth outcomes and arsenic in groundwater in New Hampshire, USA

Abstract

Background There is increasing evidence of the role of arsenic in the etiology of adverse human reproductive outcomes. Since drinking water can be a major source of arsenic to pregnant women, the effect of arsenic exposure through drinking water on human birth may be revealed by a geospatial association between arsenic concentration in groundwater and birth problems, particularly in a region where private wells substantially account for water supply, like New Hampshire, US. Methods We calculated town-level rates of preterm birth and term low birth weight (term LBW) for New Hampshire, using data for 1997-2009 and stratified by maternal age. We smoothed the rates using a locally-weighted averaging method to increase the statistical stability. The town-level groundwater arsenic values are from three GIS data layers generated by the US Geological Survey: probability of local groundwater arsenic concentration > 1 μg/L, probability > 5 μg/L, and probability > 10 μg/L. We calculated Pearson's correlation coefficients (r) between the reproductive outcomes (preterm birth and term LBW) and the arsenic values, at both state and county levels. Results For preterm birth, younger mothers (maternal age < 20) have a statewide r = 0.70 between the rates smoothed with a threshold = 2,000 births and the town mean arsenic level based on the data of probability > 10 μg/L; For older mothers, r = 0.19 when the smoothing threshold = 3,500; A majority of county level r values are positive based on the arsenic data of probability > 10 μg/L. For term LBW, younger mothers (maternal age < 25) have a statewide r = 0.44 between the rates smoothed with a threshold = 3,500 and town minimum arsenic level based on the data of probability > 1 μg/L; For older mothers, r = 0.14 when the rates are smoothed with a threshold = 1,000 births and also adjusted by town median household income in 1999, and the arsenic values are the town minimum based on probability > 10 μg/L. At the county level, for younger mothers positive r values prevail, but for older mothers it is a mix. For both birth problems, the several most populous counties - with 60-80% of the state's population and clustering at the southwest corner of the state – are largely consistent in having a positive r across different smoothing thresholds. Conclusion We found evident spatial associations between the two adverse human reproductive outcomes and groundwater arsenic in New Hampshire, US. However, the degree of associations and their sensitivity to different representations of arsenic level are variable. Generally, preterm birth has a stronger spatial association with groundwater arsenic than term LBW, suggesting an inconsistency in the impact of arsenic on the two reproductive outcomes. For both outcomes, younger maternal age has stronger spatial associations with groundwater arsenic.

Prenatal Arsenic Exposure and Birth Outcomes among a Population Residing near a Mining-Related Superfund Site

“…Previous birth outcomes studies were conducted mostly in areas of unusally high arsenic or lead exposure, among populations that also may have been at increased risk of poor overall health and nutritional status ( Huyck et al 2007 ; Xu et al 2012 ; Zheng et al 2014 ). Few birth outcomes studies have examined associations with low to moderate levels of metal exposures that are consistent with background levels in many U.S. communities ( Fei et al 2013 ; Shi et al 2015 ). Research on environmental lead exposure has demonstrated adverse effects at exposure concentrations much lower than in highly exposed populations ( Xie et al 2013 ).…”

Concentration of Lead, Mercury, Cadmium, Aluminum, Arsenic and Manganese in Umbilical Cord Blood of Jamaican Newborns

“…A study that investigated the role of air pollutants in birth outcomes has reported statistically significant associations between low birth weight and levels of aluminum (in all trimesters), calcium, nickel, silicon, and zinc (in the third trimester), as well as elemental carbon and titanium (in the first trimester) [ 33 , 34 ]. Shi et al reported preterm birth has a stronger spatial association with groundwater arsenic than term low birth weight in New Hampshire, USA [ 35 ]. Manganese is an essential mineral nutrient that plays an important role in fetal development and in other important aspects of metabolism.…”

Data Association at the Level of Narrative Plots to Support Analysis of Spatiotemporal Evolvement of Conflict: A Case Study in Nigeria

“…Compared with our approach, some investigations depend on geo-spatial or spatiotemporal association analysis to study, such as the relationship between adverse birth outcomes and arsenic in the groundwater [32] and the county potential [35]. These parametric modeling approaches [40,44,46] focus on a few data members, whereas our framework can associate more extensive data types that include more than spatial and temporal data.…”

“…For two or three studied objects, the following methods have been applied widely for association analysis. The correlation coefficient is a common criterion for detecting a binary association [32]. Some linear regression models have been applied for two or more facets [33].…”