Results of the First Pilot‐Scale Controlled Cohort Epidemiological Investigation into the Possible Health Effects of Bathing in Seawater at Langland Bay, Swansea

Abstract

AbstractA pilot study was conducted to investigate the feasibility of using adult volunteers to examine the possible health effects of bathing in UK seawaters which passed the EC bathing waters Directive. Langland Bay, near Swansea, was chosen for this experiment, which was conducted on 2 September 1989. Adult volunteers were recruited from the City of Swansea and randomly divided into bather and non‐bather groups. All volunteers were given medical examinations and medical questionnaire interviews before and after 2 September.Water quality on the day of the test was relatively unpolluted, as indexed by the commonly‐employed bacterial and viral indicator species. The detailed medical questionnaire resulted in higher reported attack rates of perceived illness in both bather and non‐bather groups than those published in previous studies, which have commonly employed a single telephone interview to acquire disease perception data. Statistically‐significant differences in the bather and non‐bather cohorts were found for the following perceived symptoms: sore throat, ear symptom, eye symptom at 3 d after 2 September, and for diarrhoea at three weeks after the experiment. The clinical tests employed failed to confirm these significant perceived symptom attack rate differentials.The significance of these results is discussed in the context of previous research protocols to demonstrate the feasibility of this novel prospective controlled cohort approach for the acquisition of scientifically robust data on the health effect of recreational water use. If taken to a full‐scale study, it is argued that this research protocol could offer considerable advantages over past methods and lead to scientifically valid water‐quality standards for recreational waters.