Oral Presentation 33rd ASM of the Australian & New Zealand Bone & Mineral Society 2023

Nonmelanoma skin cancer is associated with fewer incident fractures, more vitamin D sufficiency, greater BMD and improved bone microarchitecture in older adults (#18)

Michael Thompson 1 2 , Graeme Jones 2 , Alison Venn 2 , Saliu Balogun 2 , Flavia Cicuttini 3 , Bruna Ragaini 2 , Dawn Aitken 2
  1. Department of Endocrinology, Royal Hobart Hospital, Hobart, TAS, Australia
  2. Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
  3. Musculoskeletal Unit, Monash University, Melbourne, Victoria, Australia

Introduction

Nonmelanoma skin cancer (NMSC), a biomarker of cumulative lifetime sun exposure, is associated with reduced fracture risk later in life, but the mechanism is unknown.

 

Methods

Prospective cohort analysis of 1,099 community-dwelling adults aged 50-80 years with baseline and 10 year follow up assessments. Histopathologically-confirmed NMSC diagnosis was established by linkage with the Tasmanian Cancer Registry. BMD and vertebral deformity were by quantified by DXA, 25(OH)D by radioimmunoassay, bone microarchitecture by high resolution peripheral quantitative CT, melanin density by spectrophotometry and skin photosensitivity and clinical fracture by questionnaire. 25(OH)D <50 nmol/L was considered deficient.

 

Results

Participants with prior NMSC at baseline were less likely to sustain an incident vertebral deformity over 10 years (RR=0.73, p=0.018). There were similar reductions for other fracture types but these did not reach significance. Prior NMSC was associated with baseline (RR=1.22, p=0.007) and 10 year longitudinal (RR=6.2, p=0.011) vitamin D sufficiency and greater total body BMD (β=0.20g/cm2, p=0.046), but not falls risk (β=-0.0, p=0.62). The relationship between NMSC and bone microarchitecture was age dependent (pinteraction<0.05). In the oldest age tertile, prior NMSC was associated with higher volumetric BMD (β=55.6–60.5, p=0.002–0.01) and less porosity (β= -4.1 – -5.1, p=0.002–0.009) at cortical, compact cortical and outer transitional zones. Associations were independent of sex, BMI and skin phenotype.

 

Conclusion

Prior NMSC was associated with fewer incident fractures in community-dwelling older adults. This protective association is most likely mediated by modifiable fracture risk factors associated with an outdoor lifestyle, including 25(OH)D, BMD and bone microarchitecture.