title: Lean Mass and Body Fat Percentage Are Contradictory Predictors of Bone Mineral Density in Pre-Menopausal Pacific Island Women.
abstract: Anecdotally, it is suggested that Pacific Island women have good bone mineral density (BMD) compared to other ethnicities; however, little evidence for this or for associated factors exists. This study aimed to explore associations between predictors of bone mineral density (BMD, g/cm²), in pre-menopausal Pacific Island women. Healthy pre-menopausal Pacific Island women (age 16-45 years) were recruited as part of the larger EXPLORE Study. Total body BMD and body composition were assessed using Dual X-ray Absorptiometry and air-displacement plethysmography (n = 83). A food frequency questionnaire (n = 56) and current bone-specific physical activity questionnaire (n = 59) were completed. Variables expected to be associated with BMD were applied to a hierarchical multiple regression analysis. Due to missing data, physical activity and dietary intake factors were considered only in simple correlations. Mean BMD was 1.1 ± 0.08 g/cm². Bone-free, fat-free lean mass (LMO, 52.4 ± 6.9 kg) and age were positively associated with BMD, and percent body fat (38.4 ± 7.6) was inversely associated with BMD, explaining 37.7% of total variance. Lean mass was the strongest predictor of BMD, while many established contributors to bone health (calcium, physical activity, protein, and vitamin C) were not associated with BMD in this population, partly due to difficulty retrieving dietary data. This highlights the importance of physical activity and protein intake during any weight loss interventions to in order to minimise the loss of muscle mass, whilst maximizing loss of adipose tissue.
authors.affiliation: Institute of Food Science and Technology, Massey University, Auckland 0632, New Zealand. nzmaria.78@gmail.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Casale
authors.affiliation: Institute of Food Science and Technology, Massey University, Auckland 0632, New Zealand. p.r.vonhurst@massey.ac.nz.
authors.forename: Pamela R
authors.initials: PR
authors.lastname: von Hurst
authors.affiliation: Institute of Food Science and Technology, Massey University, Auckland 0632, New Zealand. k.l.beck@massey.ac.nz.
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Beck
authors.affiliation: School of Sport and Exercise, Massey University, Wellington 6140, New Zealand. s.p.shultz@massey.ac.nz.
authors.forename: Sarah
authors.initials: S
authors.lastname: Shultz
authors.affiliation: Institute of Food Science and Technology, Massey University, Auckland 0632, New Zealand. m.c.kruger@massey.ac.nz.
authors.forename: Marlena C
authors.initials: MC
authors.lastname: Kruger
authors.affiliation: Institute of Food Science and Technology, Massey University, Auckland 0632, New Zealand. w.j.obrien@massey.ac.nz.
authors.forename: Wendy
authors.initials: W
authors.lastname: O'Brien
authors.affiliation: Institute of Food Science and Technology, Massey University, Auckland 0632, New Zealand. C.conlon@massey.ac.nz.
authors.forename: Cathryn A
authors.initials: CA
authors.lastname: Conlon
authors.affiliation: Institute of Food Science and Technology, Massey University, Auckland 0632, New Zealand. r.kruger@massey.ac.nz.
authors.forename: Rozanne
authors.initials: R
authors.lastname: Kruger
mesh_terms: D050154:Adiposity / Q000208:ethnology; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D015519:Bone Density; D015331:Cohort Studies; D004032:Diet / Q000009:adverse effects / Q000208:ethnology; D015444:Exercise; D005260:Female; D006801:Humans; D008875:Middle Aged; D024510:Muscle Development; D009520:New Zealand / Q000453:epidemiology; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*; D050177:Overweight / Q000000981:diagnostic imaging / Q000208:ethnology / Q000503:physiopathology*; D010139:Pacific Islands / Q000208:ethnology; D017697:Premenopause; D012307:Risk Factors; D055815:Young Adult
keywords: Pacific Island; body composition; bone mineral density; dietary intake; physical activity; pre-menopausal