Abstract
A retrospective study was carried out to determine the relationship between parity and bone mineral density (BMD) in middle-aged women. Eight hundred and twenty-five woman aged 41–76 years were recruited from four general practice registers in Cambridge. Subjects were unselected as to their health status. Each subject completed a detailed health questionnaire. Participation rate was 50%. The main outcome measure was BMD measured at the spine (L2–4,n=825) and hip (neck, intertrochanter and Ward's triangle;n=817) by dual-energy X-ray absorptiometry (DXA) using the Hologic QDR-1000 densitometer. It was found that the unadjusted mean BMD was significantly higher at all sites among the parous women (p=0.031 to <0.00001), and remained significantly higher at the femoral neck (p=0.025), intertrochanter (p=0.001) and Ward's triangle (p=0.045) after adjusting for age and body mass index (BMI). Similar findings were seen after stratifying for potential confounding variables. There was a consistent upward trend of BMD with increasing parity at all sites. Parity remained a significant independent predictor of BMD at all sites after controlling for age, BMI, menopausal status, oral contraceptive and hormone replacement therapy use, smoking status and breast-feeding status in multiple linear regression analyses. There was, on average, a 1.0% increase in BMD per live birth. Our findings therefore suggest a positive relationship between parity and bone mass.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Seeley DG, Browner WS, Nevitt MC, Genant HK, Scott JC, Cummings SR, et al. Which fractures are associated with low appendicular bone mass in elderly women? Ann Intern Med 1991;115:837–42.
Elders PJM, Netelenbos JC, Lips P, Khoe E, van Ginkel FC, Hulshof KFAM, et al. Perimenopausal bone mass and risk factors. Bone Miner 1989;7:289–99.
McCance RA, Widdowson EM. Mineral metabolism of the foetus and newborn. Br Med Bull 1961;17:132–6.
Albright F, Reifenstein EC, Jr. The parathyroid glands and metabolic disease. Baltimore: Williams and Wilkins, 1948.
Nordin BEC, Roper A. Post-pregnancy osteoporosis: a syndrome? Lancet 1955;1:431–4.
Smith RW, Jr. Dietary and hormonal factors in bone loss. Fed Proc 1967;26:1737–46.
Nilsson BE. Parity and osteoporosis. Surg Gynecol Obstet 1969;129:27–8.
Aloia JF, Vaswani AN, Yeh JK, Ross P, Ellis K, Cohn SH. Determinants of bone mass in postmenopausal women. Arch Intern Med 1983;143:1700–4.
Christiansen C, Rodbro P, Heinild B. Unchanged total body calcium in normal human pregnancy. Acta Obstet Gynecol Scand 1976:55:141–3.
Wasnich R, Yano K, Vogel J. Postmenopausal bone loss at multiple skeletal sites: relationship to estrogen use. J Chron Dis 1983;36:781–90.
Walker ARP, Richardson B, Walker F. The influence of numerous pregnancies and lactations on bone dimensions in South Africa Bantu and Caucasian mothers. Cli Sci 1972;42:189–96.
Sowers MF, Crutchfield M, Jannausch M, Updike S, Corton G. A prospective evaluation of bone mineral change in pregnancy. Obstet Gynecol 1991;77:841–5.
Kritz-Silverstein D, Barrett-Connor E, Hollenbach KA. Pregnancy and lactation as determinants of bone mineral density in postmenopausal women. Am J Epidemiol 1992;136:1052–9.
Lamke B, Brundin J, Moberg P. Changes of bone mineral content during pregnancy and lactation. Acta Obstet Gynecol Scand 1977;56:217–9.
Caraceni MP, Trevisan C, Bianchi ML, Ulivieri FM, Gandolini G, Dindelli M, et al. Negative influence of pregnancy and lactation on bone mineral density. In: Christiansen C, Johansen JS, Riis BJ, editors. Osteoporosis 1987. Copenhagen, Denmark: Osteopress ApS, 1987:144–5.
Hreshchyshyn MM, Hopkins A, Zylstra S, Anbar M. Associations of parity, breast-feeding, and birth control pills with lumbar spine and femoral neck bone densities. Am J Obstet Gynecol 1988;159:318–22.
Drinkwater BL, Chesnut CH, III. Bone density changes during pregnancy and lactation in active women: a longitudinal study. Bone Miner 1991;14:153–60.
Laskey MA, Flaxman ME, Barber RW, Trafford S, Hayball MP, Lyttle KD, et al. Comparative performance in vitro and in vivo of Lunar DPX and Hologic QDR-1000 dual energy x-ray absorptiometers. Br J Radiol 1991;64:1023–9.
Paganini-Hill A, Chao A, Ross RK, Henderson BE. Exercise and other factors in the prevention of hip fractures: the Leisure World Study. Epidemiology 1991;2:16–25.
Hoffman S, Griffo JA, Kelsey JL, Gammon MD, O'Brien LA. Parity, lactation and hip fracture. Osteoporosis Int 1993;3:171–6.
The Health and Lifestyle Survey. London: Health Promotion Research Trust, 1987.
Steinberg KK, Freni-Titulaer LW, DePuey EG, Miller DT, Sgoutas DS, Coralli CH, et al. Sex steroids and bone density in premenopausal and perimenopausal women. J Clin Endocrinol Metab 1989;69:533–9.
Cushard WG, Jr, Creditor MA, Canterbury JM, Reiss E. Physiologic hyperparathyroidism in pregnancy. J Clin Endocrinol Metab 1972;34:767–71.
Davis OK, Hawkins DS, Rubin LP, Posillico JT, Brown EM, Schiff I. Serum parathyroid hormone (PTH) in pregnant women determined by an immunoradiometric assay for intact PTH. J Clin Endocrinol Metab 1988;67:850–2.
Heaney RP, Skillman TG. Calcium metabolism in normal human pregnancy. J Clin Endocrinol Metab 1971;33:661–70.
Whitehead M, Lane G, Young O, Campbell S, Abeyasekera G, Hillyard CJ, et al. Interrelations of calcium-regulating hormones during normal pregnancy. BMJ 1981;283:10–2.
Kovaric J, Woloszczuk W, Linkesch W, Pavelka R. Calcitonin in pregnancy. Lancet 1980;1:199–200.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Murphy, S., Khaw, KT., May, H. et al. Parity and bone mineral density in middle-aged women. Osteoporosis Int 4, 162–166 (1994). https://doi.org/10.1007/BF01623063
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01623063