According to the outcomes of a study published in Pain, the genetic component of chronic back pain displays a mild gender- and age-dependency. Gender differences for chronic back pain have been witnessed, with women commonly showing higher morbidity, severity, and poorer response to therapy. Genetic factors have been observed to act in an age-specific manner but never completely evaluated.

Researchers, therefore, carried out the age- and gender-stratified genome-wide association analysis and single nucleotide polymorphism-by-gender interaction assessment for chronic back pain defined as pain in the back lasting for at least three months.

On the whole, 202,077 men and 237,754 women of European ancestry from the UK Biobank were included in this study. In total, 2 and 7 nonoverlapping genome-wide loci were detected for men and women, respectively. In four independent cohorts, a male-specific locus on chromosome 10 near SPOCK2 gene was found to be replicated.

In total, 4 loci showed single nucleotide polymorphism-by-gender interaction. However, none of them illustrated formal replication. The single nucleotide polymorphism-explained heritability was greater in women (0.079 vs 0.067). A high, although not complete, genetic correlation existed between the genders (r= 0.838 ± 0.041).

The genetic correlation between the genders for chronic back pain declined with age (0.544 ± 0.157 in older subjects vs. 0.858 ± 0.049 in younger subjects). A robust genetic correlation of chronic back pain with the self-reported diagnosis of intervertebral disk degeneration was observed in men compared to women (0.889 vs 0.638).

The study offers awareness into the possible causes of age- and gender-specificity in the epidemiology and pathophysiology of chronic back pain and chronic pain at the other anatomical sites, concluded the study authors.