Association between breastfeeding and osteoporotic hip fracture in women: a dose-response meta-analysis

Abstract

Objective Approximately 300 mg of calcium a day is provided into infants to maintain the physical development of infants, and 5 to 10% bone loss occurs in women during breastfeeding. Hip fractures are considered the most serious type of osteoporotic fracture. We performed this meta-analysis to investigate the association between breastfeeding and osteoporotic hip fractures. Material and methods PubMed and Embase were searched until May 1, 2019, for studies evaluating the relationship between breastfeeding and osteoporotic hip fracture in women. The quality of the included studies was evaluated by the methodological index for non-randomized studies (MINORS). For the dose-response meta-analysis, we used the “generalized least squares for trend estimation” method proposed by Greenland and Longnecker to take into account the correlation with the log RR estimates across the duration of breastfeeding. Results Seven studies were moderate or high quality, enrolling a total of 103,898 subjects. The pooled outcomes suggested that breastfeeding can decrease the incidence of osteoporotic hip fracture (RR = 0.64 (95% CI 0.43, 0.95), P = 0.027). Dose-response analysis demonstrated that the incidence of osteoporotic hip fracture decreased with the increase of breastfeeding time. The RR and 95% CI for 3 months, 6 months, 12 months, and 24 months were RR = 0.93, 95% CI 0.88, 0.98; RR = 0.87, 95% CI 0.79, 0.96; RR = 0.79, 95% CI 0.67, 0.92; and RR = 0.76, 95% CI 0.59, 0.98, respectively, whereas no significant relationship was found between them when the duration of breastfeeding time was more than 25 months. Conclusions Our meta-analysis demonstrated that the incidence of osteoporotic hip fracture decreased with the extension of breastfeeding time. However, there is no significant relationship between them when the duration of breastfeeding time was more than 25 months.

Association of Female Reproductive Factors With Incidence of Fracture Among Postmenopausal Women in Korea

“…However, a reduced risk of hip fracture in women who breastfed was also noted. Consistent with these findings, a recent meta-analysis reported that the incidence of osteoporotic hip fracture decreased with the extension of breastfeeding time . Other researchers have reported an association between longer duration of lactation and lower BMD in the lumbar spine but not in the femoral neck or the total hip .…”

“…Consistent with these findings, a recent metaanalysis reported that the incidence of osteoporotic hip fracture decreased with the extension of breastfeeding time. 14 Other researchers have reported an association between longer duration of lactation and lower BMD in the lumbar spine but not in the femoral neck or the total hip. 45,46 Skeletal loss is more profound from trabecular bone than from cortical bone during lactation: the vertebra is primarily trabecular bone, whereas hip bones are largely cortical bone.…”

“…4,5,9,10 Although there is wide variation in BMD and fracture incidence across racial and ethnic groups, 12 epidemiologic information regarding osteoporotic fractures in Asian women and its determinants is scarce, comprising 1 Japanese study involving 250 self-reported vertebral fractures among 43 652 women 5 and 1 Chinese study with 1327 incident hip fractures among 125 336 women. 8 Furthermore, BMD levels change during pregnancy and lactation, but the long-term associations of these events with postmenopausal BMD or fracture are controversial, with protective, [13][14][15] negative, [16][17][18] and null 4,5 findings.…”

Influencia de la lactancia materna en el metabolismo mineral óseo después de la menopausia

“…In fact, during lactation, the mother supplies the fetus with around 300 mg of calcium daily, the source of which is mainly bone, which produces a loss of between 5-10% of maternal bone mass 31 , being enough for 3-6 months lactation for this loss to occur 32 . However, when studying and trying to establish the gynecological and/or obstetric factors that can influence bone mineral metabolism, some authors assess only the presence or absence of pregnancies 16 , others study the number of pregnancies 21 with no shortage of who analyzes the age at which the first pregnancy occurs 20 .…”

“…Women in both groups, lactating and non-lactating, showed similar BMD values in both the lumbar spine and the proximal end of the femur. Some studies have described that women who breastfeed have lower BMD values than those who do not 20,24,32 , but there are other authors who find the opposite: a protective effect with higher BMD values and a lower risk of densitometric osteoporosis 18,31 . A study carried out in Korea in more than one million women 41 found that the parameters that were independently associated with an increased risk of…”