Association of Blood Trihalomethane Concentrations with Risk of All-Cause and Cause-Specific Mortality in U.S. Adults: A Prospective Cohort Study

Abstract

Water chlorination can lead to the formation of disinfection byproducts, including trihalomethanes (THMs). However, few epidemiologic studies have explored associations between THM exposure and mortality. This study included 6720 adults aged ≥40 years from the National Health and Nutrition Examination Survey 1999−2012 who had blood THM concentrations quantified. A higher risk of all-cause mortality was found across increasing quartile concentrations of blood chloroform (TCM) and total THMs (TTHMs; sum of all four THMs) (both p for trend = 0.02). Adults in the highest quartile of TCM and TTHM concentrations had hazard ratios (HRs) of 1.35 (95% confidence intervals: 1.05−1.74) and 1.37 (1.05−1.79), respectively, for all-cause mortality, compared with adults in the lowest quartile. When cause-specific mortality was evaluated, a positive relationship was found between blood bromodichloromethane (BDCM), dibromochloromethane (DBCM), bromoform (TBM), total brominated THMs (Br-THMs; sum of BDCM, DBCM, and TBM), and TTHM concentrations and risk of cancer death and between blood TCM and TTHMs and risk of other cause (noncancer/nonheart disease) mortality. Our findings suggest that higher exposure to Br-THMs was associated with increased cancer mortality risk, whereas TCM was associated with a greater risk of noncancer/nonheart disease mortality.

Assessing volatile organic compounds exposure and prostate-specific antigen: National Health and Nutrition Examination Survey, 2001–2010

“…Chloroform is the most prevalent biomarker of DBPs which can be absorbed through ingestion, inhalation, and dermal contact (73). A prospective cohort study revealed a positive relationship between total brominated THMs, including Br-THMs, the sum of (BDCM, DBCM, and TBM) and TTHM concentrations, and the risk of cancer death (74). Some studies showed that long-term chloroform exposures are linked to colorectal cancer and bladder cancer (75, 76).…”

Exposure to Trihalomethanes and Bone Mineral Density in US Adolescents: A Cross-Sectional Study (NHANES)

“…Procedures for peripheral blood and tap water collection, sampling, and determination have been described in previous studies. ,, Briefly, a single blood and household water sample was collected during the examination. The concentrations of chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM) in blood and tap water were measured via solid-phase microextraction gas chromatography and mass spectrometry.…”

“…Disinfection byproducts (DBPs) are a class of contaminants indirectly generated during the process of water disinfection, through the reaction of chemical disinfectants (e.g., chlorine) with organic matter in raw water . Humans are ubiquitously exposed to DBPs through various water-use activities such as drinking water, showering or bathing, and swimming .…”

“…6,7 Disinfection byproducts (DBPs) are a class of contaminants indirectly generated during the process of water disinfection, through the reaction of chemical disinfectants (e.g., chlorine) with organic matter in raw water. 8 Humans are ubiquitously exposed to DBPs through various water-use activities such as drinking water, showering or bathing, and swimming. 9 Previous evidence for animals and humans has suggested DBP toxicity to the bone, as manifested by abnormal curvature of the thoracic spine, 10 as well as increased risk of idiopathic scoliosis and osteoarthritis.…”

Energy-Adjusted Dietary Inflammatory Index Is Associated With 5-Year All Cause and Cardiovascular Mortality Among Chronic Kidney Disease Patients

“…The age was classified to 2 groups: <65 years old (non-elderly) and ≥ 65 years old (elderly). Gender was categorized into “male” and “female.” The race was assigned to 4 groups: Mexican American, non-Hispanic white, non-Hispanic black, and others ( 17 ). Physical activity was defined as “inactive” or “active” according to the average physical activity time (“active” was defined as getting more than 75 min/week vigorous or 150 min/week moderate physical activity) ( 18 ).…”