Sandra Cooke-Hubley1, Zhiwei Gao1, Gerald Mugford1, Stephanie M Kaiser2, David Goltzman3, William D Leslie4, K Shawn Davison5, Jacques P Brown6, Linda Probyn7, Brian Lentle8, Jerilynn C Prior9, Christopher S Kovacs10. 1. Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Drive, St. John's, NL, A1B 3V6, Canada. 2. Department of Medicine, Dalhousie University, Halifax, NS, B3H 2Y9, Canada. 3. Department of Medicine, McGill University, Montreal, QC, H4A 3J1, Canada. 4. Department of Medicine, University of Manitoba, Winnipeg, MB, R2H 2A6, Canada. 5. a priori medical sciences Inc., Victoria, BC, V8R 3E3, Canada. 6. Department of Medicine, Division of Rheumatology, CHU de Quebec Research Centre, Laval University, Quebec City, QC, G1V 4G2, Canada. 7. Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, M4R 1K5, Canada. 8. Department of Radiology, University of British Columbia, Vancouver, BC, V9A 6T5, Canada. 9. Centre for Menstrual Cycle and Ovulation Research, Medicine/Endocrinology, University of British Columbia, Vancouver, BC, V5Z 1M9, Canada. 10. Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Drive, St. John's, NL, A1B 3V6, Canada. ckovacs@mun.ca.
Abstract
Parity and lactation showed no associations with incident clinical fragility fractures or radiographic vertebral compression fractures in the 16-year CaMos prospective study. Parity was associated with slightly greater decline in femoral neck but not hip or spine areal bone mineral density (aBMD), while lactation showed no associations with aBMD change. PURPOSE: Pregnancy and especially lactation cause loss of bone mass and microarchitectural changes, which temporarily increase fracture risk. After weaning, aBMD increases but skeletal microarchitecture may be incompletely restored. Most retrospective clinical studies found neutral or even protective associations of parity and lactation with fragility fractures, but prospective data are sparse. CaMos is a randomly selected observational cohort that includes ~ 6500 women followed prospectively for over 16 years. METHODS: We determined whether parity or lactation were related to incident clinical fragility fractures over 16 years, radiographic (morphometric and morphologic) vertebral fractures over 10 years, and aBMD change (spine, total hip, and femoral neck) over 10 years. Parity and lactation duration were analyzed as continuous variables in predicting these outcomes using univariate and multivariate regression analyses. RESULTS: Three thousand four hundred thirty-seven women completed 16 years of follow-up for incident clinical fractures, 3839 completed 10 years of morphometric vertebral fracture assessment, 3788 completed 10 years of morphologic vertebral fracture assessment, and 4464 completed 10 years of follow-up for change in aBMD. In the multivariate analyses, parity and lactation duration showed no associations with clinical fragility fractures, radiographic vertebral fractures, or change in aBMD, except that parity associated with a probable chance finding of a slightly greater decline in femoral neck aBMD. CONCLUSIONS: Parity and lactation have no adverse associations with clinical fragility or radiographic vertebral fractures, or the rate of BMD decline over 10 years, in this prospective, multicenter study of a randomly selected, population-based cohort of women.
Parity and lactation showed no associations with incident clinical fragility fractures or radiographic vertebral compression fractures in the 16-year CaMos prospective study. Parity was associated with slightly greater decline in femoral neck but not hip or spine areal bone mineral density (aBMD), while lactation showed no associations with aBMD change. PURPOSE: Pregnancy and especially lactation cause loss of bone mass and microarchitectural changes, which temporarily increase fracture risk. After weaning, aBMD increases but skeletal microarchitecture may be incompletely restored. Most retrospective clinical studies found neutral or even protective associations of parity and lactation with fragility fractures, but prospective data are sparse. CaMos is a randomly selected observational cohort that includes ~ 6500 women followed prospectively for over 16 years. METHODS: We determined whether parity or lactation were related to incident clinical fragility fractures over 16 years, radiographic (morphometric and morphologic) vertebral fractures over 10 years, and aBMD change (spine, total hip, and femoral neck) over 10 years. Parity and lactation duration were analyzed as continuous variables in predicting these outcomes using univariate and multivariate regression analyses. RESULTS: Three thousand four hundred thirty-seven women completed 16 years of follow-up for incident clinical fractures, 3839 completed 10 years of morphometric vertebral fracture assessment, 3788 completed 10 years of morphologic vertebral fracture assessment, and 4464 completed 10 years of follow-up for change in aBMD. In the multivariate analyses, parity and lactation duration showed no associations with clinical fragility fractures, radiographic vertebral fractures, or change in aBMD, except that parity associated with a probable chance finding of a slightly greater decline in femoral neck aBMD. CONCLUSIONS: Parity and lactation have no adverse associations with clinical fragility or radiographic vertebral fractures, or the rate of BMD decline over 10 years, in this prospective, multicenter study of a randomly selected, population-based cohort of women.