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BackgroundChildren may be at higher risk for swimming-associated illness following exposure to fecally-contaminated recreational waters. We analyzed a pooled data set of over 80,000 beachgoers from 13 beach sites across the United States to compare risks associated with the fecal indicator bacteria Enterococcus spp. (measured by colony forming units, CFU and quantitative polymerase chain reaction cell equivalents, qPCR CE) for different age groups across different exposures, sites and health endpoints.MethodsSites were categorized according to the predominant type of fecal contamination (human or non-human). Swimming exposures of varying intensity were considered according to degree of contact and time spent in the water. Health endpoints included gastrointestinal and respiratory symptoms and skin rashes. Logistic regression models were used to analyze the risk of illness as a function of fecal contamination in water as measured by Enterococcus spp. among the exposed groups. Non-swimmers (those who did not enter the water) were excluded from the models to reduce bias and facilitate comparison across groups.ResultsGastrointestinal symptoms were the most sensitive health endpoint and strongest associations were observed with Enterococcus qPCR CE at sites impacted by human fecal contamination. Under several exposure scenarios, associations between illness and Enterococcus spp. levels were significantly higher among children compared to adolescents and adults. Respiratory symptoms were also associated with Enterococcus spp. exposures among young children at sites affected by human fecal sources, although small sample sizes resulted in imprecise estimates for these associations.ConclusionUnder many exposure scenarios, children were at higher risk of illness associated with exposure to fecal contamination as measured by the indicator bacteria Enterococcus spp. The source of fecal contamination and the intensity of swimming exposure were also important factors affecting the association between Enterococcus spp. and swimming-associated illness.

The beach environment creates many barriers to effective sun protection, putting beachgoers at risk for sunburn, a well-established risk factor for skin cancer. Our objective was to estimate incidence of sunburn among beachgoers and evaluate the relationship between sunburn incidence and sun-protective behaviors. A secondary analysis, of prospective cohorts at 12 locations within the U.S. from 2003 to 2009 (n = 75,614), were pooled to evaluate sunburn incidence 10-12 days after the beach visit. Behavioral and environmental conditions were cross-tabulated with sunburn incidence. Multivariable logistic regression was used to estimate the association between new sunburn and sun-protective behaviors. Overall, 13.1% of beachgoers reported sunburn. Those aged 13-18 years (16.5%), whites (16.0%), and those at beach locations along the Eastern Seaboard (16.1%), had the highest incidence of sunburn. For those spending ≥5 h in the sun, the use of multiple types of sun protection reduced odds of sunburn by 55% relative to those who used no sun protection (Odds Ratio = 0.45 (95% Confidence Interval:0.27-0.77)) after adjusting for skin type, age, and race. Acute health effects of sunburn tend to be mild and self-limiting, but potential long-term health consequences are more serious and costly. Efforts to encourage and support proper sun-protective behaviors, and increase access to shade, protective clothing, and sunscreen, can help prevent sunburn and reduce skin cancer risk among beachgoers.

Background and objective: Noninvasive salivary biomarkers can be used to assess the cumulative subclinical health impacts of social and environmental stressors. We evaluated seven salivary biomarkers of neuroendocrine and immune functions and a group index of physiological dysregulation based on these biomarkers in a pilot survey in a socioeconomically disadvantaged population. Results: Participants recruited at subsidized public housing projects in Denver, Colorado, completed a sociodemographic, behavioral, and health questionnaire and used passive drool samplers to collect five saliva samples over the course of 1 day. Samples were tested for the neuroendocrine biomarkers alpha-amylase, cortisol, and dehydroepiandrosterone (DHEA) as well as immune system/inflammation biomarkers C-reactive protein (CRP), interleukin (IL)-1β, IL-6 and total immunoglobulin A (IgA). A composite Inflammation and Physiological Dysregulation Index (IPDI) was calculated as a count of potentially unhealthy values of dichotomized biomarkers. In 20 individuals who completed the survey (average age 46 years, 75% females), allergy to house dust was significantly associated with increased IPDI (adjusted for age) and significantly increased odds of potentially unhealthy values of total IgA, IL-1β, and CRP. Age, obesity, diabetes, allergy to pollen, recent loss of employment, and depression, anxiety, and stress scores from the standard DASS-21 questionnaire were positively but not significantly (0.05 < p < 0.2) associated with IPDI. This project demonstrated an application of a composite index based on noninvasive salivary biomarkers to assess subclinical health impacts of chronic social stressors. [ABSTRACT FROM AUTHOR]

Potential pathways linking urban green spaces to improved health include relaxation, stress alleviation, and improved immune system functioning. Epigenetic age acceleration (EAA) is a composite biomarker of biological aging based on DNA methylation measurements; it is predictive of morbidity and mortality. This cross-sectional study of 116 adult residents of a metropolitan area in central North Carolina investigated associations between exposure to residential green spaces and EAA using four previously developed epigenetic age formulas. DNA methylation tests of white blood cells were conducted using Illumina MethylationEPIC v1.0 assays. EAA values were calculated as residuals from the linear regression model of epigenetic age on chronological age. Residential greenness was characterized using tree cover, total vegetated land cover, and normalized difference vegetation index (NDVI) data. An interquartile range (IQR) increase in distance-to-residence weighted average greenness within 500 m of residence was consistently associated with a reduced EAA adjusted for sociodemographic covariates, smoking status, white blood cell fractions, and the two-dimensional spline function of geographic coordinates. The reduction in the EAA estimates for the four EAA measures ranged from − 1.0 to − 1.6 years for tree cover, from − 1.2 to − 1.5 years for vegetated land cover, and from − 0.9 to − 1.3 years for the NDVI; 11 of the 12 associations were statistically significant (p < 0.05). This study produced new evidence linking reduced epigenetic aging to greater greenness near residences. [ABSTRACT FROM AUTHOR]

Swimming and recreating in lakes, oceans, and rivers is common, yet the literature suggests children may be at greater risk of illness following such exposures. These effects might be due to differences in immunity or differing behavioral factors such as poorer hygiene, longer exposures to, and greater ingestion of potentially contaminated water and sand. We pooled data from 12 prospective cohorts (n=68,685) to examine exposures to potentially contaminated media such as beach water and sand among children compared with adults, and conducted a simulation using self-reported time spent in the water and volume of water swallowed per minute by age to estimate the total volume of water swallowed per swimming event by age category. Children aged 4-7 and 8-12 years had the highest exposures to water, sand, and algae compared with other age groups. Based on our simulation, we found that children (6-12 years) swallow a median of 36 ml (90th percentile=150 ml), whereas adults aged ≥35 years swallow 9 ml (90th percentile=64 ml) per swimming event, with male children swallowing a greater amount of water compared with females. These estimates may help to reduce uncertainty surrounding routes and durations of recreational exposures and can support the development of chemical and microbial risk assessments.

BackgroundColiphages have been proposed as indicators of fecal contamination in recreational waters because they better mimic the persistence of pathogenic viruses in the environment and wastewater treatment than fecal indicator bacteria. We estimated the association between coliphages and gastrointestinal illness and compared it with the association with culturable enterococci.MethodsWe pooled data from six prospective cohort studies that enrolled coastal beachgoers in California, Alabama, and Rhode Island. Water samples were collected and gastrointestinal illness within 10 days of the beach visit was recorded. Samples were tested for enterococci and male-specific and somatic coliphages. We estimated cumulative incidence ratios (CIR) for the association between swimming in water with detectable coliphage and gastrointestinal illness when human fecal pollution was likely present, not likely present, and under all conditions combined. The reference group was unexposed swimmers. We defined continuous and threshold-based exposures (coliphage present/absent, enterococci >35 vs. ≤35 CFU/100 ml).ResultsUnder all conditions combined, there was no association between gastrointestinal illness and swimming in water with detectable coliphage or enterococci. When human fecal pollution was likely present, coliphage and enterococci were associated with increased gastrointestinal illness, and there was an association between male-specific coliphage level and illness that was somewhat stronger than the association between enterococci and illness. There were no substantial differences between male-specific and somatic coliphage.ConclusionsSomatic coliphage and enterococci had similar associations with gastrointestinal illness; there was some evidence that male-specific coliphage had a stronger association with illness than enterococci in marine waters with human fecal contamination.

ObjectivesTo provide summary estimates of gastroenteritis risks and illness burden associated with recreational water exposure and determine whether children have higher risks and burden.MethodsWe combined individual participant data from 13 prospective cohorts at marine and freshwater beaches throughout the United States (n = 84 411). We measured incident outcomes within 10 days of exposure: diarrhea, gastrointestinal illness, missed daily activity (work, school, vacation), and medical visits. We estimated the relationship between outcomes and 2 exposures: body immersion swimming and Enterococcus spp. fecal indicator bacteria levels in the water. We also estimated the population-attributable risk associated with these exposures.ResultsWater exposure accounted for 21% of diarrhea episodes and 9% of missed daily activities but was unassociated with gastroenteritis leading to medical consultation. Children aged 0 to 4 and 5 to 10 years had the most water exposure, exhibited stronger associations between levels of water quality and illness, and accounted for the largest attributable illness burden.ConclusionsThe higher gastroenteritis risk and associated burden in young children presents important new information to inform future recreational water quality guidelines designed to protect public health.

Use of fecal indicator bacteria (FIB) for monitoring beach water quality is based on their co-occurrence with human pathogens, a relationship that can be dramatically altered by fate and transport processes after leaving the human intestine. We conducted a prospective cohort study at Avalon Beach, California (USA), where the indicator relationship is potentially affected by the discharge of sewage-contaminated groundwater and by solar radiation levels at this shallow, relatively quiescent beach. The goals of this study were to determine: 1) if swimmers exposed to marine water were at higher risk of illness than non-swimmers; 2) if FIB measured in marine water were associated with swimmer illness, and; 3) if the associations between FIB and swimmer health were modified by either submarine groundwater discharge or solar radiation levels. There were 7317 individuals recruited during the summers of 2007-08, 6165 (84%) of whom completed follow-up within two weeks of the beach visit. A total of 703 water quality samples were collected across multiple sites and time periods during recruitment days and analyzed for FIB using both culture-based and molecular methods. Adjusted odds ratios (AOR) indicated that swimmers who swallowed water were more likely to experience Gastrointestinal Illness (GI Illness) within three days of their beach visit than non-swimmers, and that this risk was significantly elevated when either submarine groundwater discharge was high (AOR [95% CI]:2.18 [1.22-3.89]) or solar radiation was low (2.45 [1.25-4.79]). The risk of GI Illness was not significantly elevated for swimmers who swallowed water when groundwater discharge was low or solar radiation was high. Associations between GI Illness incidence and FIB levels (Enterococcus EPA Method 1600) among swimmers who swallowed water were not significant when we did not account for groundwater discharge, but were strongly associated when groundwater discharge was high (1.85 [1.06, 3.23]) compared to when it was low (0.77 [0.42, 1.42]; test of interaction: P = 0.03). These results demonstrate the need to account for local environmental conditions when monitoring for, and making decisions about, public health at recreational beaches. The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency.

BackgroundStudies of health risks associated with recreational water exposure require investigators to make choices about water quality indicator averaging techniques, exposure definitions, follow-up periods, and model specifications; however, investigators seldom describe the impact of these choices on reported results. Our objectives are to report illness risk from swimming at a marine beach affected by nonpoint sources of urban runoff, measure associations between fecal indicator bacteria levels and subsequent illness among swimmers, and investigate the sensitivity of results to a range of exposure and outcome definitions.MethodsIn 2009, we enrolled 5674 people in a prospective cohort at Malibu Beach, a coastal marine beach in California, and measured daily health symptoms 10-19 days later. Concurrent water quality samples were analyzed for indicator bacteria using culture and molecular methods. We compared illness risk between nonswimmers and swimmers, and among swimmers exposed to various levels of fecal indicator bacteria.ResultsDiarrhea was more common among swimmers than nonswimmers (adjusted odds ratio = 1.88 [95% confidence interval = 1.09-3.24]) within 3 days of the beach visit. Water quality was generally good (fecal indicator bacteria levels exceeded water quality guidelines for only 7% of study samples). Fecal indicator bacteria levels were not consistently associated with swimmer illness. Sensitivity analyses demonstrated that overall inference was not substantially affected by the choice of exposure and outcome definitions.ConclusionsThis study suggests that the 3 days following a beach visit may be the most relevant period for health outcome measurement in recreational water studies. Under the water quality conditions observed in this study, fecal indicator bacteria levels were not associated with swimmer illness.

Exposure to contaminated recreational waters (defined by levels of fecal and other types of indicator bacteria) is associated with adverse health outcomes. The principal health outcome studied previously has been gastrointestinal illness. Although many studies included reports of frequent skin complaints (e.g. rash or itch) following recreational water exposure, no systematic reviews have examined the association between indicator levels and skin-related symptoms. Twenty relevant peer-reviewed studies were identified. The relative risks (swimmers vs. non-swimmers) of skin-related symptoms among those exposed to recreational water with bacterial indicator concentrations above threshold levels were determined using meta-analysis. Similarly, the relative risks (swimmers vs. non-swimmers) of skin-related complaints after exposure to water with bacterial indicator concentrations below threshold levels were determined. The ratio of these odds ratios (ROR) was then computed for each indicator. The risk of skin-related symptoms was significantly elevated in marine water with high levels of total coliforms ROR 1.86, (95% CI 1.21, 2.87); fecal coliforms ROR 1.45 (95% CI 1.02, 2.07); E. coli ROR 1.98, (95% CI 1.43, 2.75); enterococci ROR 2.04 (95% CI 1.34, 3.09) and fecal streptococci ROR 1.70 (95% CI 1.07, 2.71). However, no significant associations with water quality indicators were demonstrated for the freshwater indicators examined (total coliform, fecal coliform, E. coli). Swimmers exposed to marine water at high levels of several indicator bacteria experience a significant increase in skin-related symptoms compared to non-swimmers. This relationship was not demonstrated in freshwater settings.

Risk assessments and intervention trials have been used by the U.S. Environmental Protection Agency to estimate drinking water health risks. Seldom are both methods used concurrently. Between 2001 and 2003, illness data from a trial were collected simultaneously with exposure data, providing a unique opportunity to compare direct risk estimates of waterborne disease from the intervention trial with indirect estimates from a risk assessment. Comparing the group with water treatment (active) with that without water treatment (sham), the estimated annual attributable disease rate (cases per 10,000 persons per year) from the trial provided no evidence of a significantly elevated drinking water risk [attributable risk=-365 cases/year, sham minus active; 95% confidence interval (CI) , -2,555 to 1,825]. The predicted mean rate of disease per 10,000 persons per person-year from the risk assessment was 13.9 (2.5, 97.5 percentiles: 1.6, 37.7) assuming 4 log removal due to viral disinfection and 5.5 (2.5, 97.5 percentiles: 1.4, 19.2) assuming 6 log removal. Risk assessments are important under conditions of low risk when estimates are difficult to attain from trials. In particular, this assessment pointed toward the importance of attaining site-specific treatment data and the clear need for a better understanding of viral removal by disinfection. Trials provide direct risk estimates, and the upper confidence limit estimates, even if not statistically significant, are informative about possible upper estimates of likely risk. These differences suggest that conclusions about waterborne disease risk may be strengthened by the joint use of these two approaches. Key words: drinking water, gastrointestinal, intervention trial, microbial risk assessment, waterborne pathogens.

We conducted a randomized, triple-blinded home drinking water intervention trial to determine if a large study could be undertaken while successfully blinding participants. Households were randomized 50:50 to use externally identical active or sham treatment devices. We measured the effectiveness of blinding of participants by using a published blinding index in which values >0.5 indicate successful blinding. The principal health outcome measured was "highly credible gastrointestinal illness" (HCGI). Participants (n=236) from 77 households were successfully blinded to their treatment assignment. At the end of the study, the blinding index was 0.64 (95% confidence interval 0.51-0.78). There were 103 episodes of HCGI during 10,790 person-days at risk in the sham group and 82 episodes during 11,380 person-days at risk in the active treatment group. The incidence rate ratio of disease (adjusted for the clustered sampling) was 1.32 (95% CI 0.75, 2.33) and the attributable risk was 0.24 (95% CI -0.33, 0.57). These data confirm that participants can be successfully blinded to treatment group assignment during a randomized trial of an in-home drinking water intervention.