Risk of gastroenteritis among triathletes in relation to faecal pollution of fresh waters.

BACKGROUND: We conducted a prospective cohort study among endurance athletes to investigate the effects of microbiological water quality on the risk of gastroenteritis after bathing in fresh waters that meet current water quality standards. We aimed to establish quantitative relationships, in order to evaluate current bathing water standards. METHODS: The study was spread over two summers, during which 827 triathletes (swimmers) in seven Olympic distance triathlons and 773 participants in 15 run-bike-runs (non-swimming controls) participated. Intensive water quality monitoring was used to assess exposure to faecal indicator organisms and detailed questionnaires were used to collect data on the occurrence of health complaints and potential confounding factors. RESULTS: The microbiological water quality at the time of the triathlons met current Dutch and European bathing water standards. Dependent on the case definition studied, gastroenteritis developed in 0.4-5.2% of swimmers and 0.1-2.1% of non-swimmers in the week following exposure (odds ratio [OR] = 1.6-2.3). Attack rates and burden of disease varied with the case definition used. Among swimmers, the attack rate of gastroenteritis was significantly increased when the geometric mean concentration of thermotolerant coliforms in the water at the time of exposure was > or = 220/100 ml or the geometric mean concentration of Escherichia coli was > or = 355/100 ml (OR comparing high versus low exposure 2.9-4.7 dependent on the case definition studied). Thermotolerant coliform concentrations at these triathlons ranged from 100/100 ml (the EU guide level) to 960/100 ml (the EU imperative level is 2000/100 ml). Below the threshold levels attack rates were comparable with attack rates among non-swimmers. A relation with other indicators of faecal pollution was not observed. CONCLUSIONS: We observed that swimming in fresh waters that met the European imperative level for thermotolerant coliforms but failed the European guide level was associated with a significant risk of gastroenteritis among triathletes. This means that the current European imperative level for thermotolerant coliforms provides insufficient protection to gastrointestinal illness for those who are comparable with triathletes.

Salivary levels of immunoglobulin A in triathletes.

We investigated whether the physical exercise of an olympic distance triathlon affected the salivary IgA excretion of triathletes, as a biomarker for mucosal immune defence. 42 triathletes participated in the study. It was found that the salivary flow rate was decreased significantly after the race, thereby resulting in a significant reduction of the total salivary IgA output. The salivary IgA concentration (mg IgA/ml) did not differ, but expressed as total salivary protein, a significant reduction was observed. This was on the account of the salivary protein concentration (mg protein/ml), which was significantly increased. In contrast to the IgA secretion, the salivary amylase activity was increased significantly after the race. Therefore, our data suggest that the exercise of a triathlon may decrease the level of IgA-mediated immune protection at the mucosal surface. As triathletes may during the race be exposed to micro-organisms present in the swimming water, a decreased IgA-mediated immunity during the race may pose triathletes at an increased risk of infections.

An outbreak of cryptosporidiosis in the Netherlands.

A hospital microbiologist in Spijkenisse, in the south west of the Netherlands - who had recently attended a parasitology course - identified cryptosporidial oocysts in stools from a patient with diarrhoea on 16 August 1995. Re-examination of 89 stool spe

Risk of otitis externa after swimming in recreational fresh water lakes containing Pseudomonas aeruginosa.

OBJECTIVE: To determine whether an outbreak of otitis externa was due to bathing in recreational fresh water lakes and to establish whether the outbreak was caused by Pseudomonas aeruginosa in the water. DESIGN: Matched case-control study. SETTING: The Achterhoek area, the Netherlands. SUBJECTS: 98 cases with otitis externa and 149 controls matched for age, sex, and place of residence. MAIN OUTCOME MEASURES: Odds ratios for type of swimming water and frequency of swimming; presence of P aeruginosa in ear swabs and fresh water lakes. RESULTS: Otitis externa was strongly associated with swimming in recreational fresh water lakes in the previous two weeks (odds ratio 15.5 (95% confidence interval) 4.9 to 49.2) compared with non-swimming). The risk increased with the number of days of swimming, and subjects with recurrent ear disease had a greatly increased risk. The lakes met the Dutch bathing water standards and those set by the European Commission for faecal pollution in the summer of 1994, but P aeruginosa was isolated from all of them, as well as from the ear swabs of 78 (83%) of the cases and 3 (4%) of the controls. CONCLUSIONS: Even when current bathing water standards are met, swimming can be associated with a substantial risk of otitis externa because of exposure to P aeruginosa. People with recurrent ear disease should take special care when swimming in waters containing P aeruginosa.

Body iron stores and mortality due to cancer and ischaemic heart disease: a 17-year follow-up study of elderly men and women.

BACKGROUND: Increased body iron stores have been suggested as a risk factor for cancer and ischaemic heart disease (IHD). However, all studies carried out to date have focused on relatively young populations although the elderly may also be at increased risk. METHODS: We investigated the association between body iron stores and mortality due to cancer and IHD in a 17-year follow-up study of 260 non-institutionalized elderly people aged 64-87 years. Iron status was assessed in 1971 by means of the haemoglobin level, transferrin saturation and total iron binding capacity (TIBC). Information about the vital status and causes of death was obtained in 1988. RESULTS: Among women mortality due to cancer was inversely related to TIBC; the relative risk for the highest tertile of TIBC, adjusted for age, smoking and alcohol intake was 0.05 (95% confidence interval (CI): 0.007-0.39). The risk of mortality due to all-causes was also inversely associated with TIBC. Among men, no association between body iron stores and mortality due to cancer was observed. Mortality due to IHD was not clearly associated with body iron status. Among men, the adjusted relative risk decreased slightly per tertile of transferrin saturation, but this trend was only of borderline significance (P = 0.10). CONCLUSIONS: These results suggest that body iron stores are a risk factor for mortality due to cancer in postmenopausal women. This may be due to accumulation of stored iron among women after menopause. No clear associations with mortality due to IHD were observed in either elderly men or elderly women.

The prevalence of morbidity in the oldest old, aged 85 and over: a population-based survey in Leiden, The Netherlands.

The Leiden 85-plus study has investigated the prevalence of morbidity in the total population of the Dutch community of Leiden (population 105 000) aged 85 and over, including both independently living and institutionalized elderly. The participation rate of 94% of all living elderly (n = 1037) and 78% of the initial cohort (n = 1259) was exceptionally high. Information was obtained on past and present diseases by taking a medical history. The life-time prevalence for arteriosclerosis and malignancies was 31.9% and 9.7% respectively. High prevalences were found for the non-lethal disabling disorders of hearing and visual impairment (44.4% and 49.9%, respectively) and urinary incontinence (25.6%). The authors conclude that establishing a classical medical diagnosis in the oldest old, which was the goal of this study, is not complete without assessing its effect on the functional ability and the quality of life of the individual.