Constitutive melanin density is associated with prevalent and short-term, but not long-term, incident fracture risk in older Caucasian adults

Thompson, M. J. W.; Jones, G.; Balogun, S.; Aitken, D. A.

Affiliations

¹Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia

Abstract and keywords

Summary: Higher cutaneous melanin reduces vitamin D3 production. This may increase fracture risk. We found that cutaneous melanin density was associated with prevalent and short-term, but not long-term, incident fracture risk in older Caucasian adults. Melanin density either acts as a surrogate marker or its relationship with fracture changes with time.

Introduction: Higher cutaneous melanin reduces vitamin D3 production. This may impact lifetime vitamin D status and increase fracture risk. This study aimed to describe the relationship between spectrophotometrically determined constitutive melanin density, prevalent and incident fractures in a cohort of exclusively older Caucasian adults.

Methods: 1072 community-dwelling adults aged 50–80 years had constitutive melanin density quantified using spectrophotometry. Participants were followed up at 2.5 (n = 879), 5 (n = 767), and 10 (n = 571) years after the baseline assessment. Prevalence and number of symptomatic fractures were assessed by questionnaire.

Results: Higher melanin density was independently associated with greater prevalence of any fracture (RR 1.08, p = 0.03), vertebral fracture (RR 1.41, p = 0.04) and major fracture (RR 1.12, p = 0.04) and the number of fractures (RR 1.09, p = 0.04) and vertebral fractures (RR 1.47, p = 0.04) in cross-sectional analysis. At the 2.5-year follow-up, higher melanin density was associated with incident fractures (RR 1.42, p = 0.01) and major fractures (RR 1.81, p = 0.01) and the number of incident fractures (RR 1.39, p = 0.02) and major fractures (RR 2.14, p = 0.01). The relationship between melanin density and incident fracture attenuated as the duration of follow-up increased and was not significant at the 5- or 10-year follow-up.

Conclusions: Constitutive melanin density was associated with prevalent and short-term, but not long-term, incident fracture risk in older Caucasian adults. This suggests melanin density either acts as a surrogate marker for an unmeasured fracture risk factor or the relationship between melanin density and fracture changes with time.

Keywords: Fractures; Melanin density; Skin pigmentation

Links

DOI: 10.1007/s00198-020-05304-4

PubMed: 32239236

WoS: 000522894000002

History

Received: 2019-08-25

Accepted: 2020-01-15

Online: 2020-04-01

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Cited By (1)

Year	Entry
2020	Thompson MJW, Jones G, Balogun SA, Aitken DA. Skin photosensitivity is associated with 25-hydroxyvitamin D and BMD but not fractures independent of melanin density in older caucasian adults. Calcif Tiss Int. October 2020;107(4):335-344.