Prostate Gland Enlargement Does Not Increase ALS Risk, Study Reports

Men with benign prostatic hyperplasia (BPH) — prostate gland enlargement — are not at greater risk of amyotrophic lateral sclerosis (ALS) and similar disorders, according to a nationwide study in Denmark.

“We found no evidence of an increased risk of ALS and other MND [motor neuron diseases] among men with diagnosed BPH compared with men from the general population,” the researchers said.

The study, “Risk of amyotrophic lateral sclerosis and other motor neuron disease among men with benign prostatic hyperplasia: a population-based cohort study,” appeared in the journal BMJ Open.

Sleep disruption has been associated with a greater risk of Alzheimer’s disease, likely due to reduced clearance of the key proteins tau and amyloid beta. Similarly, ALS is characterized by the accumulation of protein aggregates within neurons.

Although a correlation between sleep disruption and disease risk also could occur in people with ALS and related disorders, including progressive bulbar palsy, it had not been assessed by prior studies.

BPH is a common, age-related disorder in men. Most men with BPH have nocturia — frequent urination at night — which causes sleep deprivation and insomnia. Given that, a team from Denmark assessed whether men with BPH are at a greater risk of having ALS and other motor neuron diseases (MND).

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“Since BPH is a common, treatable condition that often interrupts sleep, an increased risk of MND in this population would support a pathogenetic role of sleep disruption in this disorder and could have public health implications,” the researchers said.

A total of 223,131 men with a BPH diagnosis between January 1, 1980 and November 30, 2013, and no prior diagnosis of motor neuron diseases, were included in the study. This group was compared with 1,115,642 men with no BPH diagnosis (controls) identified with the Danish Civil Registration System. The median age was 71.6 years in both groups.

Using the Danish National Patient Registry, the scientists found a BPH prevalence of 10.8% among men aged 50 or older.

Over the 34 years of follow-up, the researchers found 227 cases of ALS or other motor neuron disease in men with BPH, and 1,094 such cases in the control group. The corresponding incidence rates were similar in the two groups — 0.13 versus 0.12 per 1000 person-years at risk — as was the 34-year risk of motor neuron diseases (0.16% in both groups). Researchers note that person-years is a measure that sums actual follow-up duration in each patient and is higher with more years in study.

This risk of ALS or other motor neuron disease also was similar in patients followed over more than 10 years, “when prolonged nocturia and sleep disruption from BPH might be expected to have the greatest effect on disease risk,” the scientists said. Analyzing the data by year of BPH diagnosis — 1980-1993 compared with 1994-2013 — also led to similar risks.

The data further showed that the median age of motor neurons disease diagnosis was 74.7 years in men with BPH and 75.0 years in the controls.

“BPH is not associated with an increased risk of ALS and other [motor neuron disease],” the team said.

“This finding implies that sleep disruptions resulting from nocturnal awakenings in middle-age and older men with BPH are not substantially associated with risk of [motor neuron disease],” the researchers added.