Environmental Manganese and Cancer Mortality Rates by County in North Carolina: An Ecological Study

Abstract

Manganese is an element essential for health in trace amounts, but toxic at higher exposures. Since manganese is replacing lead in gasoline globally, evaluation of potential cancer effects is essential. To determine whether environmental manganese is related to cancer at the county level in North Carolina (n = 100 counties; North Carolina 2000 population = 8,049,313), we carried out an ecological study using data from the North Carolina State Center for Health Statistics, North Carolina Geological Survey, US Geological Survey, and US Census. County-level all-cause and cancer mortality rates between 1997 and 2001 reported in deaths per 100,000 population associated by multivariable regression with logarithmically transformed groundwater (microgram per liter) and airborne (microgram per cubic meter) manganese concentrations by county measured between 1973 and 1979 (water) and in 1996 (air). Models controlled for county characteristics. Median all-cause and cancer mortality rates by county in North Carolina (1997-2001) exceeded those of the USA (2000). For each log increase in groundwater manganese concentration, there was a corresponding county-level increase of 12.10 deaths/100,000 population in all-site cancer rates, 2.84 deaths/100,000 in colon cancer rates, and 7.73 deaths/100,000 in lung cancer rates. For each log increase in airborne manganese concentration, there was a corresponding county-level decrease of 8.10 deaths/100,000 population in all-site cancer rates, 3.28 deaths/100,000 in breast cancer rates, and 3.97 deaths/100,000 in lung cancer rates. Neither groundwater nor air concentrations of manganese correlated with county-level all-cause or prostate cancer death rates. These are the first data we know of to document a potential relationship between environmental manganese and population-level cancer death rates. The positive association between groundwater manganese and specific cancer mortality rates might be a function of the high concentrations measured, while the inverse relationship between air manganese and death rates might point toward adequate (e.g., healthy) county-level manganese exposures. Since manganese is replacing lead in gasoline globally, these ecological findings should be confirmed at the individual level or in animal models.

Plasma Concentrations of Some Trace Element and Heavy Metals in Patients with Metastatic Colon Cancer

“…It is therefore important to evaluate the potential cancer effects of Mn on the public. Spangler et al performed an ecological study for evaluation of potential cancer effects of Mn and they reported that either groundwater or air concentrations of Mn is correlated with increase in allsite cancer rates including colon carcinoma [33]. In our current study, serum level of Mn was elevated in colon cancer patients with respect to control healthy group.…”

Heavy metal concentration in groundwater from Besant Nagar to Sathankuppam, South Chennai, Tamil Nadu, India

“…The higher concentrations are due to rainwater being precipitated on dumping site of waste solids, which releases Mn from solid waste, from automobile emission (Loranger et al 1994). Higher concentration of Mn will have neurological effect when continuously consumed (Zoni et al 2007;WHO 2011a, b;Spangler and Reid 2010). As a result, the concentration of heavy metals such as Fe, Pb, Zn, Cr, Co and Mn increases in POM compared to PRM season.…”

The Mutagenicity and Carcinogenicity of Inorganic Manganese Compounds: A Synthesis of The Evidence

“…Study unsuited to establishment of causal association. (Spangler and Reid, 2010) Note. Comments appear in italics; FeMn: ferromanganese; FeSi: ferrosilicon; CI: 95% confidence intervals; PAHs: polyaromatic hydrocarbons; SiMn: silicomanganese; SIR: standardized incidence ratio; SMR: standardized mortality ratio.…”

“…An ecological study on the population of North Carolina used multivariate analysis techniques to study the relationship between county-level death rates for total cancer, lung, breast, colon, and prostate cancer, and Mn levels in groundwater and ambient air (Spangler and Reid 2010). The study drew on data collected at the state level on a population of 8,049,313 for deaths in the period 1997-2001.…”

“…No marked association between water or air Mn levels and prostate cancer rates was identified in this study. With regard to the apparent negative association of some cancers with atmospheric Mn levels, Spangler and Reid (2010) proposed that the low airborne levels may serve as surrogates for an intake at a level at which the protective effects of this metal predominate over any adverse consequences. It was also speculated that the positive association with groundwater concentration may be real and reflect differences in route of exposure, dose level, age or susceptibility.…”