Nutrition Sciences Program, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada (BF-B), and the Discipline of Medicine, Faculty of Medicine, Memorial University, St John's, Canada (JT, AG, HZ, and GS).
The melanin-concentrating hormone receptor 1 (MCHR1) is a G protein-coupled receptor that regulates energy balance and body composition in animal models. Inconsistent effects of MCHR1 polymorphisms on energy homeostasis in humans may partly be attributable to environmental factors.
We examined the effect of 4 single nucleotide polymorphisms (rs133073, rs133074, rs9611386, and rs882111) in the MCHR1 gene on body composition as well as energy-related lifestyle factors (diet and physical activity). We also examined the effect of gene-lifestyle interactions on body composition.
A total of 1153 participants (248 men and 905 women) from the cross-sectional Complex Diseases in the Newfoundland Population: Environment and Genetics (CODING) study were genotyped by using probe-based chemistry validated assays. Diet and physical activity were estimated by using validated frequency questionnaires, and body composition was assessed by using dual-energy X-ray absorptiometry.
Three polymorphisms (rs9611386, rs882111, and rs133073) were associated with differences in body-composition measurements (all P
Department of Food, Water and Cosmetics, Norwegian Institute of Public Health, Oslo, Norway; Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA.
Sensitization to food allergens and food allergic reactions are mostly caused by ingesting the allergen, but can also occur from exposure via the respiratory tract or the skin. Little is known about exposure to food allergens in the home environment.
The objective of this study was firstly to describe the frequency of detection of allergens from fish, egg, milk, and peanut in mattress dust collected from homes of 13-year-old adolescents and secondly to identify home characteristics associated with the presence of food allergen contamination in dust.
Food allergens were measured by dot blot analysis in mattress dust from 143 homes in Oslo, Norway. We analysed associations between home characteristics (collected by parental questionnaires and study technicians) and food allergens by multivariate regression models.
Fish allergen was detected in 46%, peanut in 41%, milk in 39%, and egg allergen in 22% of the mattress dust samples; only three samples contained none of these allergens. All four food allergens were more frequently detected in mattresses in small dwellings (
Childhood nonviral gastroenteritis is a priority for various public health authorities. Given that waterborne transmission is sometimes incriminated during investigation of gastroenteritis outbreaks, the authors hypothesized that watershed characteristics may influence the occurrence of this disease and could contribute additional insights for better prevention and control. The study described here aimed to investigate watershed characteristics in relation to nonviral gastroenteritis and specifically three bacterial and parasitic forms of childhood gastroenteritis to assess their relative importance in the province of Quebec, Canada. Information on children aged 0-4 years with bacterial or parasitic enteric infections reported through ongoing surveillance between 1999 and 2006 in the province of Quebec was collected. Factors measured at the municipal and watershed levels were analyzed using multilevel models with a Poisson distribution and log link function. Childhood nonviral gastroenteritis, giardiasis, and campylobacteriosis were positively associated with small ruminants and cattle density. Childhood salmonellosis was positively associated with cattle density. Also, childhood campylobacteriosis incidence was positively associated with larger watershed agricultural surface. In addition to local agroenvironmental factors, this analysis revealed an important watershed effect.
Department of Animal and Plant Sciences, University of Sheffield, , Western Bank, Sheffield S10 2TN, UK, Department of Environmental Health, Jagiellonian University Medical College, , Grzegorzecka 20, Krakow 31-531, Poland.
Individual variation in nutritional status has direct implications for fitness and thus is crucial in shaping patterns of life-history variation. Nevertheless, it is difficult to measure in natural populations, especially in humans. Here, we used longitudinal data on individual life-histories and annual crop yield variation collected from pre-industrial Finnish populations experiencing natural mortality and fertility to test the validity of first birth interval (FBI; time between marriage and first birth) as a surrogate measure of nutritional status. We evaluated whether women with different socio-economic groups differ in length of FBI, whether women of poorer socio-economic status and experiencing lower crop yields conceive slower following marriage, and whether shorter FBI is associated with higher lifetime breeding success. We found that poorer women had longer FBI and reduced probability of giving birth in months with low food availability, while the FBI of richer women was not affected by variation in food availability. Women with shorter FBI achieved higher lifetime breeding success and a faster reproductive rate. This is, to our knowledge, the first study to show a direct relationship between environmental conditions and speed of childbirth following marriage, highlighting the value of FBI as an indicator of nutritional status when direct data are lacking.
Studies conducted in the mid-1980s and early 1990s demonstrated that persistent organic pollutants (POPs) and metals were reaching the Arctic ecosystem at unexpectedly high levels, many of which had no Arctic or Canadian sources. Epidemiological and toxicological studies in Canada and in other countries have found that these contaminants may pose a risk to human health. The objective of this paper is to provide the foundation for the discussion on future northern human health research under the Northern Contaminants Program (NCP) in Canada. This short discussion of human health priorities will help guide a path forward for future northern human health research in Canada to address on-going and new health concerns related to contaminants exposure in the Canadian Arctic.
Cites: Sci Total Environ. 2010 Oct 15;408(22):5165-23420728918
Department of Environmental Science, Aarhus University, Roskilde, Denmark; National Pollen and Aerobiology Research Unit, University of Worcester, Worcester, United Kingdom. Electronic address: firstname.lastname@example.org.
Ann Allergy Asthma Immunol. 2013 Dec;111(6):548-54
Very few studies on human exposure to allergenic pollen have been conducted using direct methods, with background concentrations measured at city center monitoring stations typically taken as a proxy for exposure despite the inhomogeneous nature of atmospheric pollen concentrations. A 2003 World Health Organization report highlighted the need for an improved understanding of the relation between monitoring station data and actual exposure.
To investigate the relation between grass pollen dose and background concentrations measured at a monitoring station, to assess the fidelity of monitoring station data as a qualitative proxy for dose, and to evaluate the ratio of dose rate to background concentration.
Grass pollen dose data were collected in Aarhus, Denmark, in an area where grass pollen sources were prevalent, using Nasal Air Samplers. Sample collection lasted for approximately 25 to 30 minutes and was performed at 2-hour intervals from noon to midevening under moderate exercise by 2 individuals.
A median ratio of dose rate to background concentration of 0.018 was recorded, with higher ratio values frequently occurring at 12 to 2 PM, the time of day when grass species likely to be present in the area are expected to flower. From 4 to 8 PM, dose rate and background concentration data were found to be strongly and significantly correlated (rs = 0.81). Averaged dose rate and background concentration data showed opposing temporal trends.
Where local emissions are not a factor, background concentration data constitute a good quantitative proxy for inhaled dose. The present ratio of dose rate to background concentration may aid the study of dose-response relations.
Research has shown that hip fracture risk increases with latitude; hypothetically due to reduced sunlight exposure and its effect on bone quality. Sweden, with large differences in latitude and UV radiation, is ideal to study in order to analyse the association between latitude and UV radiation on age- and sex-specific hip fracture rates among elderly.
Aggregated (2006-2008) age- and sex-specific hip fracture data was obtained for each Swedish municipality as well as the municipality's latitudinal coordinates and aggregated (2006-2008) UV radiation levels. Pearson correlations were calculated between hip fracture incidence rates, latitude and UV radiation. Independent t tests were calculated on tertile-categorized latitudinal data in order to investigate the difference in hip fracture risk between these categories.
Statistically significant correlations were seen in all groups between hip fracture incidence rates and latitude as well as UV radiation. The independent t tests showed that this correlation was mainly due to high incidence rates in high latitude municipalities.
Statistically significant correlations are seen between hip fracture incidence rates and latitude as well as UV radiation in Sweden and the northern parts of Sweden have an increased risk of hip fractures compared to the middle and southern parts. To our knowledge this is the first study using a national discharge register that shows this relationship and provides a starting point for further research to investigate why populations in northern Sweden have a higher risk of hip fractures compared to other Swedish regions.
Genes and the environment both influence the metabolic processes that determine fitness. To illustrate the importance of metabolism for human brain evolution and health, we use the example of lipid energy metabolism, i.e. the use of fat (lipid) to produce energy and the advantages that this metabolic pathway provides for the brain during environmental energy shortage. We briefly describe some features of metabolism in ancestral organisms, which provided a molecular toolkit for later development. In modern humans, lipid energy metabolism is a regulated multi-organ pathway that links triglycerides in fat tissue to the mitochondria of many tissues including the brain. Three important control points are each suppressed by insulin. (1) Lipid reserves in adipose tissue are released by lipolysis during fasting and stress, producing fatty acids (FAs) which circulate in the blood and are taken up by cells. (2) FA oxidation. Mitochondrial entry is controlled by carnitine palmitoyl transferase 1 (CPT1). Inside the mitochondria, FAs undergo beta oxidation and energy production in the Krebs cycle and respiratory chain. (3) In liver mitochondria, the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) pathway produces ketone bodies for the brain and other organs. Unlike most tissues, the brain does not capture and metabolize circulating FAs for energy production. However, the brain can use ketone bodies for energy. We discuss two examples of genetic metabolic traits that may be advantageous under most conditions but deleterious in others. (1) A CPT1A variant prevalent in Inuit people may allow increased FA oxidation under nonfasting conditions but also predispose to hypoglycemic episodes. (2) The thrifty genotype theory, which holds that energy expenditure is efficient so as to maximize energy stores, predicts that these adaptations may enhance survival in periods of famine but predispose to obesity in modern dietary environments.
Abstract The role of environmental reservoirs in H. pylori transmission remains uncertain due to technical difficulties in detecting living organisms in sources outside the stomach. Residents of some Canadian Arctic communities worry that contamination of the natural environment is responsible for the high prevalence of H. pylori infection in the region. This analysis aims to estimate associations between exposure to potential environmental sources of biological contamination and prevalence of H. pylori infection in Arctic Canada. Using data from 3 community-driven H. pylori projects in the Northwest and Yukon Territories, we estimated effects of environmental exposures on H. pylori prevalence, using odds ratios (OR) and 95% confidence intervals (CI) from multilevel logistic regression models to adjust for household and community effects. Investigated exposures include: untreated drinking water; livestock; dogs; cats; mice or mouse droppings in the home; cleaning fish or game. Our analysis did not identify environmental exposures associated clearly with increased H. pylori prevalence, except any exposure to mice or mouse droppings (OR = 4.6, CI = 1.2-18), reported by 11% of participants. Our multilevel models showed H. pylori clustering within households, but environmental exposures accounted for little of this clustering; instead, much of it was accounted for by household composition (especially: having infected household members; number of children). Like the scientific literature on this topic, our results do not clearly implicate or rule out environmental reservoirs of H. pylori; thus, the topic remains a priority for future research. Meanwhile, H. pylori prevention research should seek strategies for reducing direct transmission from person to person.
Enteric illness associated with foodborne and waterborne disease is thought to be common in some Canadian Indigenous communities. This study aimed to understand the lived experience of acute gastrointestinal illness (AGI), including symptoms and severity, perceived causes, and healthcare seeking behaviors of AGI in the small Inuit community of Rigolet, Canada. A concurrent mixed quantitative and qualitative methods design was used. Two cross-sectional retrospective surveys provided quantitative data to examine self-reported AGI symptoms and the distribution of potential risk factors in the community. Qualitative data from in-depth interviews with one-third of AGI cases were analyzed using a constant-comparative method to describe symptoms and severity, identify perceived risk factors, and explore health seeking behavior of AGI in Rigolet. Of the survey respondents reporting AGI, most reported symptoms of diarrhea without vomiting, followed by diarrhea with vomiting, and vomiting without diarrhea. The most common secondary symptoms included stomach cramps and abdominal pain, nausea, and extreme tiredness. Community members identified potential risk factors for AGI that reflect the epidemiology triad (host, agent, and environmental factors), including hygiene, retail food, tap water, boil water advisories, and personal stress. Risk aversion and healthcare seeking behaviors reflected the core constructs of the Health Belief Model (perceived susceptibility, severity, and benefits and barriers to action). Understanding community experience, perspectives, and beliefs related to AGI is useful for public health practitioners and health care providers. This information is important especially considering the relatively high estimated burden of AGI and the relatively low healthcare seeking behaviors in some Indigenous communities compared to national estimates. Moreover, the mixed-methods approach used to understand the burden of AGI could be extended to other health research in Indigenous contexts.
Different approaches are being taken to clarify the role of various factors in the development of physical activity behaviors. Genetic studies are a new area of physical activity research and also the motives for physical activity have been widely studied. The purpose of this paper is to review the findings emerging from the longitudinal genetic studies on leisure-time physical activity and to evaluate the associations between motivational factors and leisure-time physical activity. The focus is to review recent findings of longitudinal Finnish twin studies. The results of the latest longitudinal Finnish twin studies point to the existence of age-specific genetic and environmental influences on leisure-time physical activity. Variations in environmental factors seem to explain the observed deterioration in leisure-time physical activity levels. A decline in genetic influences is seen first from adolescence to young adulthood and again from the age of thirty to the mid-thirties. In the Finnish twin participants, mastery, physical fitness, and psychological state were the major motivation factors associated with consistent leisure-time physical activity behavior. The results also indicate that intrinsic motivation factors may be important for engagement in leisure-time physical activity.
Factors significant for clinical-and-labor prognosis in elderly patients with ischemic heart disease after surgical myocardial revascularization are considered in the article. The authors demonstrate that for each level of the problem there are their own significant factors. Besides, the most essential correlations between investigated factors are marked out. The results obtained will enable to determine more correctly clinical-and-labor prognosis for patients with ischemic heart disease and develop their efficient rehabilitation programs. It is demonstrated that elderly patients have some features of vital activity restriction which are necessary to take into account while medical social expertise and rehabilitation program development.
Several environmental exposures, including infection with Epstein-Barr virus, low levels of vitamin D and smoking are established risk factors for multiple sclerosis (MS). Also, high hygienic standard and infection with parasites have been proposed to influence MS risk. The aim of this study was to investigate the influence of various environmental exposures on MS risk in a Norwegian cohort, focusing on factors during childhood related to the hygiene hypothesis.
A questionnaire concerning environmental exposures, lifestyle, demographics and comorbidity was administrated to 756 Norwegian MS patients and 1090 healthy controls. Logistic regression was used to calculate odds ratio (OR) with 95% confidence interval (CI) for the risk of MS associated with the variables infectious mononucleosis, severe infection during childhood, vaccination and animals in the household during childhood. Age, gender, HLA-DRB1*15:01, smoking and infectious mononucleosis were included as covariates. General environmental exposures, including tobacco use, were also evaluated.
Infectious mononucleosis was confirmed to be significantly associated with increased MS risk, also after adjusting for the covariates (OR?=?1.79, 95% CI: 1.12-2.87, p?=?0.016). The controls more often reported growing up with a cat and/or a dog in the household, and this was significant for ownership of cat also after adjusting for the covariates (OR?=?0.56, 95% CI: 0.40-0.78, p?=?0.001). More patients than controls reported smoking and fewer patients reported snuff use.
In this Norwegian MS case-control study of environmental exposures, we replicate that infectious mononucleosis and smoking are associated with increased MS risk. Our data also indicate a protective effect on MS of exposure to cats during childhood, in accordance with the hypothesis that risk of autoimmune diseases like MS may increase with high hygienic standard.
Cites: N Engl J Med. 2000 Aug 17;343(7):481-9210944566
The world's northernmost harbor seal (Phoca vitulina) population, which inhabits Svalbard, Norway, constitutes a genetically distinct population. The present study reports concentrations of 14 PCBs, 5 chlordanes, p,p'-DDT, p,p'-DDE, hexachlorobenzene (HCB), mirex, and, a-, ß-and ?-hexachlorocyclohexane (HCH) in blubber, and pentachlorophenol, 4-OH-heptachlorostyrene, 10 OH-PCBs and 14 perfluoroalkyl substances in plasma of live-captured harbor seals from this population (4 males, 4 females, 4 juveniles), sampled in 2009-2010. Concentrations of PCB 153, p,p'-DDE, oxychlordane, a-HCH and mirex and perfluoroalkyl sulfonates in Svalbard harbor seals were considerably lower than harbor seal from more southerly populations, while concentrations of HCB, OH-PCBs and perfluoroalkyl carboxylates were similar for harbor seals from Svalbard and southern areas. Concentrations of PCBs and pesticides in the Svalbard harbor seals were 60-90% lower than levels determined a decade ago in this same population. Current concentrations of legacy POPs are not considered a health risk to the harbor seals from Svalbard.
The prevention of suicidal behavior is one of the most important tasks for mental health clinicians. Although a few studies have indicated an increased risk of suicidal behavior among individuals with attention-deficit/hyperactivity disorder, the development of more effective ways of identifying and modifying the risk is hampered by our limited understanding of the underlying mechanisms for this association.
To explore whether attention-deficit/hyperactivity disorder and suicidal behavior share genetic and environmental risk factors.
Matched cohort design across different levels of family relatedness recorded from January 1, 1987, to December 31, 2009. We identified 51?707 patients with attention-deficit/hyperactivity disorder (through patient and prescribed drug registers) in Sweden and their relatives by linking longitudinal population-based registers. Control participants were matched 1:5 on sex and birth year.
Any record of suicide attempt or completed suicide defined by discharge diagnoses of the International Classification of Diseases.
Individuals with attention-deficit/hyperactivity disorder (probands) had increased risks of attempted and completed suicide, even after adjusting for comorbid psychiatric disorders (odds ratio [OR]?=?3.62 [95% CI, 3.29-3.98] and 5.91 [95% CI, 2.45-14.27], respectively). The highest familial risk was observed among first-degree relatives (attempted suicide: OR?=?2.42 [95% CI, 2.36-2.49] among parents of probands with ADHD and OR?=?2.28 [95% CI, 2.17-2.40] among full siblings of probands with ADHD; completed suicide: OR?=?2.24 [95% CI, 2.06-2.43] and OR?=?2.23 [1.83-2.73], respectively), whereas the risk was considerably lower among more genetically distant relatives (attempted suicide: OR?=?1.59 [95% CI, 1.47-1.73] among maternal half siblings, OR?=?1.57 [95% CI, 1.45-1.70] among paternal half siblings, and OR?=?1.39 [95% CI, 1.35-1.43] among cousins; completed suicide: OR?=?1.51 [95% CI, 1.08-2.10], OR?=?2.02 [95% CI, 1.47-2.79], and OR?=?1.51 [95% CI, 1.36-1.67], respectively). These familial aggregation patterns remained similar across sex, after excluding relatives with attention-deficit/hyperactivity disorder and probands with suicidal behavior, and after excluding probands and relatives with severe comorbid disorders.
Attention-deficit/hyperactivity disorder is associated with an increased risk of both attempted and completed suicide. The pattern of familial risks across different levels of relatedness suggests that shared genetic factors are important for this association. This is an important first step toward identifying the underlying mechanisms for the risk of suicidal behavior in patients with attention-deficit/hyperactivity disorder and suggests that individuals with attention-deficit/hyperactivity disorder and their family members are important targets for suicide prevention and treatment.
Road traffic noise is a common environmental nuisance, which has been thought to increase the risk of many types of health problems. However, population-level evidence often remains scarce. This study examined whether road traffic noise is associated with self-rated health and use of psychotropic medication in a cohort of public sector employees.
Data are from the Finnish Public Sector Study cohort. Geographical information system (GIS) was used to link modeled outdoor road traffic noise levels (L den) to residential addresses of 15 611 men and women with cross-sectional survey responses on self-rated health and register-based information on the use of antidepressants, anxiolytics, and hypnotics. High trait anxiety scores were used to identify potentially vulnerable individuals. The analyses were run with logistic regression models adjusting for individual and area-level variables. All participants were blind to the aim of the study.
Mean level of road traffic noise at participants' home addresses was 52 decibels (dB) (standard deviation 8.1). Noise level >60 dB versus =45 dB was associated with poor self-rated health in men [odds ratio (OR) 1.58, 95% confidence interval (95% CI) 1.14-2.21]. Further stratification revealed that the association was evident only among men with high trait anxiety scores (OR 2.23, 95% CI 1.28-3.89). No association was found with psychotropic medication use or among women.
Exposure to road traffic noise was not associated with increased use of psychotropic medication, although it was associated with weakened self-rated health among men.
Comment In: Scand J Work Environ Health. 2014 May 1;40(3):211-324668139
The current paper presents a pilot study of interactive assessment using information and communication technology (ICT) to evaluate the knowledge, skills and abilities of staff with no formal education who are working in Swedish elderly care.
Theoretical and practical assessment methods were developed and used with simulated patients and computer-based tests to identify strengths and areas for personal development among staff with no formal education.
Of the 157 staff with no formal education, 87 began the practical and/or theoretical assessments, and 63 completed both assessments. Several of the staff passed the practical assessments, except the morning hygiene assessment, where several failed. Other areas for staff development, i.e. where several failed (>50%), were the theoretical assessment of the learning objectives: Health, Oral care, Ergonomics, hygiene, esthetic, environmental, Rehabilitation, Assistive technology, Basic healthcare and Laws and organization. None of the staff passed all assessments. Number of years working in elderly care and staff age were not statistically significantly related to the total score of grades on the various learning objectives.
The interactive assessments were useful in assessing staff members' practical and theoretical knowledge, skills, and abilities and in identifying areas in need of development. It is important that personnel who lack formal qualifications be clearly identified and given a chance to develop their competence through training, both theoretical and practical. The interactive e-assessment approach analyzed in the present pilot study could serve as a starting point.
A large proportion of breast cancer cases are thought related to environmental factors. Identification of specific geographical areas with high risk (clusters) may give clues to potential environmental risk factors. The aim of this study was to investigate whether clusters of breast cancer existed in space and time in Denmark, using 33 years of residential histories.
We conducted a population-based case-control study of 3138 female cases from the Danish Cancer Registry, diagnosed with breast cancer in 2003 and two independent control groups of 3138 women each, randomly selected from the Civil Registration System. Residential addresses of cases and controls from 1971 to 2003 were collected from the Civil Registration System and geo-coded. Q-statistics were used to identify space-time clusters of breast cancer. All analyses were carried out with both control groups, and for 66% of the study population we also conducted analyses adjusted for individual reproductive factors and area-level socioeconomic indicators.
In the crude analyses a cluster in the northern suburbs of Copenhagen was consistently found throughout the study period (1971-2003) with both control groups. When analyses were adjusted for individual reproductive factors and area-level socioeconomic indicators, the cluster area became smaller and less evident.
The breast cancer cluster area that persisted after adjustment might be explained by factors that were not accounted for such as alcohol consumption and use of hormone replacement therapy. However, we cannot exclude environmental pollutants as a contributing cause, but no pollutants specific to this area seem obvious.
Cites: Am J Epidemiol. 2009 Dec 1;170(11):1358-6419854807
Cites: Int J Health Geogr. 2008;7:4618700963
Cites: Scand J Public Health. 2011 Jul;39(7 Suppl):22-521775345
Cites: Scand J Public Health. 2011 Jul;39(7 Suppl):42-521775350
Cites: Cancer Epidemiol. 2011 Oct;35(5):438-4121227766
Cites: Int J Environ Health Res. 2012;22(3):232-4822129067
Cites: Scand J Public Health. 2012 Jun;40(4):391-722786925
Cites: Occup Environ Med. 2012 Aug;69(8):551-622645325
Celiac disease (CD) is a major public health problem with estimated 1-3% prevalence in the general population. In recent years an increase in CD prevalence has been reported both in Sweden and worldwide. This study aimed at examining the annual incidence rate of biopsy-proven celiac disease among children in Sweden over a 36-year period, to assess variations by age, sex and birth cohort, and to assess the clinical impact of these changes.
The National Swedish Childhood CD Register was used to identify 9107 children aged 0-14.9 years who were diagnosed with CD during the period 1973 to 2009. From 1973 to 1990 the register covered 15% of the nation, this increased to 40% during 1991-1997; a full national coverage was obtained from 1998 onwards. Estimations for the annual incidence rate, cumulative incidence and clinical impact by age groups, calendar month and birth cohorts were made.
CD incidence is continuing to increase in the child population aged 2-14.9 years. A continued variation in CD incidence was observed in children aged 0-1.9 years, characterized by a marked decrease in most recent years. The median age at diagnosis has increased from 1.0 year in the 1970s to 6.8 years in 2009. The average number of new cases has risen from ~200 during 1973-1983 to ~600 during 2004-2009. In the birth cohorts of 2000-2002 the cumulative incidence even exceeded that of the epidemic cohorts at comparable ages. The highest cumulative incidence was observed in the birth cohorts of 1985-1995 and 2000-2002.
CD risk varies between birth cohorts, suggesting cyclic environmental and/or lifestyle risk factors in CD etiology. More research on underlying risk factors is required in order to move forward with preventive strategies.
Cites: Gut. 2013 Jan;62(1):43-5222345659
Cites: N Engl J Med. 2002 Sep 19;347(12):911-2012239261
In November 2010, ˜27,000 (˜45%) inhabitants of Östersund, Sweden, were affected by a waterborne outbreak of cryptosporidiosis. The outbreak was characterized by a rapid onset and high attack rate, especially among young and middle-aged persons. Young age, number of infected family members, amount of water consumed daily, and gluten intolerance were identified as risk factors for acquiring cryptosporidiosis. Also, chronic intestinal disease and young age were significantly associated with prolonged diarrhea. Identification of Cryptosporidium hominis subtype IbA10G2 in human and environmental samples and consistently low numbers of oocysts in drinking water confirmed insufficient reduction of parasites by the municipal water treatment plant. The current outbreak shows that use of inadequate microbial barriers at water treatment plants can have serious consequences for public health. This risk can be minimized by optimizing control of raw water quality and employing multiple barriers that remove or inactivate all groups of pathogens.