Physical activity may prevent gallstones formation by reducing bile stasis and plasma triglycerides and elevating high-density lipoprotein cholesterol levels. This prospective study investigated the relationship of physical activity and symptomatic gallstones in both sexes, using a questionnaire validated against physiological measurements.
A total of 25 639 volunteers, aged 40–74 years, were recruited into the European Prospective Investigation of Cancer, Norfolk and completed a questionnaire recording occupational and recreational physical activity. This questionnaire was validated earlier against measures of energy expenditure and cardio-respiratory fitness. Participants were ranked into four groups of physical activity. The cohort was monitored over 14 years for symptomatic gallstones. The primary outcome was hazard ratios (HR) of developing gallstones at 5 years, calculated using Cox regression modelling. HRs were adjusted for body mass index, alcohol, hormone replacement therapy and parity. Further analysis of a binary variable compared the highest level of physical activity against a combination of the lowest three levels.
After 5 years of follow-up, 135 participants (69.6% women) developed symptomatic gallstones. Comparing the highest level of physical activity against the lowest three levels, the multivariable analysis at 5 years was HR=0.30 (95% confidence interval=0.14–0.64, P=0.002). After 14 years the findings were attenuated (HR=0.70, 95% confidence interval=0.49–1.01, P=0.055).
The highest level of physical activity was associated with a 70% decreased risk of symptomatic gallstones after 5 years. This association may be causal as there are consistent experimental and epidemiological data for a protective effect. Physical activity should be accurately measured in studies investigating gallstones aetiology.
aNorfolk and Norwich University Hospital NHS Trust
bSchool of Medicine, Health Policy and Practice, University of East Anglia, Norwich
cDepartment of Public Health and Primary Care, Institute of Public Health, University of Cambridge
dMRC Epidemiology Unit, Cambridge, UK
Correspondence to Dr Paul Banim, MBBS, 2nd Floor Medical School Building, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
Tel: +44 1603 597191; fax: +44 1603 593752; e-mail: email@example.com
Received 16 October 2009 Accepted 5 January 2010