Waist circumference (WC), a simple measure of central obesity, appears to be predictive of the severity of lower urinary tract symptoms (LUTS) in men, a study from the United States has found.

Men with moderate to severe LUTS, > 40 years old with no previous treatment for LUTS were divided into tertiles according to WC: < 90 cm, 90-99 cm and > 100 cm. A total of 409 men, aged 40–91, median57.6 years, were studied, with 153, 137 and 119 men in the respective tertiles.

Patients were tested for a range of parameters: International Prostate Symptom Score (IPSS), prostate volume, serum prostate specific antigen (PSA), ejaculatory dysfunction, erectile dysfunction (ED), coronary artery disease, hypertension, cholesterol and type 2 diabetes mellitus. Results were then compared between the three WC groups.

WC was significantly and positively associated with prostate volume. Although there was no difference in overall prostate volume between the groups, there was a significant increase seen in men with large prostates > 50 g in the group with WC > 100 cm. Forty per cent of those with WC >100 cm had a prostate volume > 50 g (i.e. significantly increased), versus 28% of those with WC < 90 cm.

PSA level also rose with increasing WC, from 1.87 in those100 cm.

Overall prevalence of LUTS, as measured by the IPSS, did not differ between the groups, but the proportion of men with severe symptoms (IPSS 20-35) was significantly higher in men with WC > 100 cm (p = 0.003).

Sexual dysfunction increased with WC; 32% of men reported ED in the < 90 cm group compared with 75% of men in the > 100 cm group and ejaculatory dysfunction affected 21% and 65% in these respective groups.

Predictably, the incidence of other more established elements of the metabolic syndrome varied between the groups.

As WC increased from the bottom to the top group, hypertension prevalence increased from 15% to 34%, coronary artery disease from 8% to 29%, diabetes from 11% to 33% and mean serum cholesterol increased significantly from 148 mg/dl to 254 mg/dl.

The metabolic syndrome is characterised by insulin resistance with compensatory high levels of circulating insulin, and for some time has been recognised as the unifying link between type 2 diabetes, coronary heart disease, hypertension, obesity and dyslipidaemia.

The metabolic syndrome is highly prevalent in western societies, with estimates of approximately 35% of the adult population of the USA affected.

More recently, it has been hypothesised that male voiding dysfunction and ED should also be considered part of the metabolic syndrome, and there is increasing research interest in this area.

In women, extreme weight loss e.g. after bariatric surgery has led to significant improvement in urinary symptoms.

This study emphasises the importance of considering cardiovascular risk and diabetes in men presenting with LUTS and/or ED.

There is evidence that increasing exercise and weight loss will lead to an improvement in LUTS and erectile function. Therefore lifestyle advice aiming at these factors should form a routine part of primary care management of these conditions.

Dr Jonathan Rees

• Lee R, Chung D, Chughtai B et al. Central obesity as measured by waist circumference is predictive of severity of lower urinary tract symptoms. BJU Int 2012;doi:10.1111