Some good news to ease the guilt of Christmas excess - all those drinks may actually be protecting you from benign prostatic hyperplasia (BPH).

BPH has a high prevalence among older men, affecting 70% of men aged 60-69 and 80% of those aged 80 and above. The exact aetiology of male lower urinary tract symptoms (LUTS) and BPH - the so-called LUTS/BPH complex - remains unclear, but causal factors such as sex steroid hormones, genetic predisposition and age have been cited in the past.

However, more recently, an association between BPH and metabolic dysfunction has been postulated, suggesting links between factors that increase the risk of cardiovascular disease (e.g. obesity, diabetes and dyslipidaemia) with the risk of BPH and LUTS.

As modifiable lifestyle factors play a major role in systemic metabolic disturbance and cardiovascular disease, it is possible that similar lifestyle factors may modify the risk of developing LUTS/BPH. Moderate alcohol intake reduces the risk of cardiovascular disease, so could it also decrease the risk of developing BPH?

A systematic review and meta-analysis has examined this possibility. The researchers, from the United States, carried out a meta-analysis of published studies looking at alcohol intake, BPH and LUTS. They analysed abstracted data with random effects models to obtain pooled odds ratios (ORs) of adjusted effects estimates.

A total of 19 studies met the inclusion criteria, with data on more than 120,000 men analysed. Fourteen of these studies demonstrated a significantly reduced risk of BPH or LUTS with increased alcohol intake. A total of 16 studies were eligible for pooled analysis, of which 12 used BPH as the primary outcome.

Alcohol intake was stratified, by amount consumed, into six levels: less than or equal to 5g/day; less than or equal to 12g/day; less than or equal to 15g/day; less than or equal to 24g/day; less than or equal to 36g/day and >36g/day. Consumption of alcohol was found to decrease, significantly or marginally, the likelihood of BPH in all six strata (p values 0.08, 0.01,

Compared with no alcohol intake, an alcohol intake of 36g/day or greater was associated with a 35% decreased likelihood of BPH (OR 0.65, 95% CI 0.58-0.74, p

However, of the four studies that considered LUTS as a whole (including storage symptoms such as urgency and frequency) as the primary outcome, rather than BPH, only one found a decreased likelihood of LUTS with increasing alcohol intake, the other three found an increased risk. The authors quite reasonably speculate that this may be due to the increased diuretic effect of alcohol plus the well known impact of alcohol on bladder-mediated LUTS e.g. overactive bladder syndrome.

The authors conclude that greater alcohol consumption is associated with a decreased likelihood of BPH but not LUTS. However, they add that: 'Further studies are needed to determine the mechanism by which alcohol modifies BPH risk and whether alterations in alcohol intake may alter clinical progression.'

So another factor to help justify the glass of wine at the end of a busy day at the coalface of general practice. A word of warning though - 36g of alcohol equates to 4½ units of alcohol per day, or nearly

32 units per week, so to gain the maximum benefit in terms of BPH risk reduction, you need to sail pretty close to the mark on recommended weekly alcohol intake.