Impact of Competing Risk of Mortality on Association of Weight Loss With Risk of Central Body Fractures in Older Men: A Prospective Cohort Study

Abstract

To determine the association of weight loss with risk of clinical fractures at the hip, spine and pelvis (central body fractures [CBF]) in older men with and without accounting for the competing risk of mortality, we used data from 4,523 men (mean age 77.5 years). Weight change between baseline and follow-up (mean 4.5 years between examinations) was categorized as moderate loss (loss ≥10%), mild loss (loss 5% to <10%), stable (<5% change) or gain (gain ≥5%). Participants were contacted every 4 months after the follow-up examination to ascertain vital status (deaths verified by death certificates) and ask about fractures (confirmed by radiographic reports). Absolute probability of CBF by weight change category was estimated using traditional Kaplan-Meier method and cumulative incidence function accounting for competing mortality risk. Risk of CBF by weight change category was determined using conventional Cox proportional hazards regression and subdistribution hazards models with death as a competing risk. During an average of 8 years, 337 men (7.5%) experienced CBF and 1,569 (34.7%) died before experiencing this outcome. Among men with moderate weight loss, CBF probability was 6.8% at 5 years and 16.9% at 10 years using Kaplan-Meier vs. 5.7% at 5 years and 10.2% at 10 years using a competing risk approach. Men with moderate weight loss compared with those with stable weight had a 1.6-fold higher adjusted risk of CBF (HR 1.59, 95% CI 1.06–2.38) using Cox models that was substantially attenuated in models accounting for competing mortality risk and no longer significant (subdistribution HR 1.16, 95% CI 0.77–1.75). Results were similar in analyses substituting hip fracture for CBF. Older men with weight loss who survive are at increased risk of CBF, including hip fracture. However, ignoring the competing mortality risk among men with weight loss substantially overestimates their longterm fracture probability and relative fracture risk.

Protein Intake and Risk of Falls: A Prospective Analysis in Older Adults

“…Interestingly, in participants in the Health ABC study who lost weight, higher protein intake was related to lower lean muscle loss, whereas in those with a stable weight, no association was found . Similarly, some studies related unintentional weight loss to an increased risk of frailty fractures and falls . Thus two of the frailty criteria, namely unintentional weight loss and muscle strength, were associated with protein intake.…”

“…35 Similarly, some studies related unintentional weight loss to an increased risk of frailty fractures and falls. 38,39 Thus two of the frailty criteria, namely unintentional weight loss and muscle strength, were associated with protein intake. Moreover, frailty was associated with the risk of falls.…”

Associations of Body Composition Trajectories with Bone Mineral Density, Muscle Function, Falls, and Fractures in Older Men: The Concord Health and Ageing in Men Project

“…The fact that weight loss intention may influence risk of subsequent functional decline, despite the fact that it may not influence weight loss-associated effects on bone loss and fracture risk (1,3), indicates that intentionality, as well as weight loss strategies employed, may be important considerations in understanding these relationships. However, these factors were not assessed in the present study.…”

“…Weight loss is associated with increased bone loss and fractures in older adults (1,2), and these associations have been demonstrated to persist for up to eight years (3,4). This increase in fracture risk is likely explained by loss of bone mineral density (BMD) (5), and also weight loss-associated declines in physical function (4,6) which may lead to increased incidence of falls.…”

Weight loss since early adulthood, later life risk of fracture hospitalizations, and bone mineral density: a prospective cohort study of 0.5 million Chinese adults

“…However, the findings of the association between weight loss and fractures at sites other than hip, such as upper limb [6,7] and spine [7,16], were inconsistent. Also, these three available studies were conducted in either postmenopausal women [6,7] or men ≥ 65 years old [16] and to address the association of weight loss after baseline with the risk of fracture at various body sites during the follow-up. Despite the evidence available in the Western populations, the findings might not be fully applied to the Asian populations including Chinese.…”