Other variables that would have been interesting to include, but were unavailable, were for instance anti-citrullinated peptide antibody (ACPA) status and composite disease activity scores, as well as several established risk factors for fractures in the general population (e.g. smoking, alcohol use, body mass index, menopause and comorbidities), prevalent osteoporosis diagnosis and anti-osteoporotic treatment. The gene discussed is PRTN3; the disease is osteoporosis.