Fracture Risk in Older Adults With Sarcopenia, Low Bone Mass
Fracture Risk in Older Adults With Sarcopenia, Low Bone Mass
The majority of men were white, with little difference in race between the groups. Sarcopenic men with or without low BMD were older than those in the other groups, but there was little variability in smoking and alcohol consumption between the groups. A higher percentage of women with low BMD with or without sarcopenia were white, and these women tended to be older. Total hip and femoral neck BMD were the lowest in the low BMD and sarcopenia group in men and in the low BMD with or without sarcopenia groups in women. Unlike sarcopenic women, sarcopenic men had more IADL impairments and more falls.
Eight hundred seventy (16%) men experienced a nonspine fracture (402 (12%) normal; 11 (14%) sarcopenia; 421 (21%) low BMD; 36 (32%) low BMD and sarcopenia). The age-adjusted incidence of nonspine fracture was similar in normal men (13.2/1,000) and those with sarcopenia alone (15.1/1,000) but was much higher in men with low BMD and sarcopenia (46.5/1,000) (Figure 1). Men with low BMD and sarcopenia had a risk of fracture that was almost four times as great as that of normal men (HR= 3.75, 95% CI = 2.64–5.32) (Table 3). Men with sarcopenia alone did not have a statistically significantly higher risk of fractures (HR = 1.19, 95% CI = 0.65–2.17), but the risk of fracture in those with low BMD alone (HR = 1.79, 95% CI = 1.56–2.05) was intermediate between normal men and men with both conditions. These associations remained significant after adjusting for important covariates (Table 3). The interaction term between sarcopenia and low BMD was not statistically significant (P = .06). Low BMD was associated with fracture risk after adjusting for sarcopenia (HR = 1.97, 95% CI = 1.72–2.25). Similarly, sarcopenia was associated with fracture risk after adjusting for low BMD (HR = 2.25, 95% CI = 1.68–3.03). Exclusion of traumatic fractures showed somewhat similar results (Table 3, p-interaction = .11).
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Figure 1.
Age-adjusted incidence rate (per 1,000) of nonspine fractures according to bone mineral density (BMD) and body composition. In men, the incidence rate was the highest for participants with low BMD and sarcopenia. Men with only one or neither condition had lower incidence rates. In women, the incidence rates were similar for participants with low BMD, with or without sarcopenia. Women with neither condition and with sarcopenia alone had lower rates of nonspine fractures.
Two hundred seventy-two (25%) women experienced a nonspine fracture (31 (10%) normal, 7 (15%) sarcopenic, 194 (33%) low BMD, 40 (32%) low BMD and sarcopenia). The age-adjusted incidence of fracture ranged from 13.9 per 1,000 in normal women to approximately 40 per 1,000 in women with low BMD or low BMD and sarcopenia (Figure 1). There was little sex difference in fracture incidence rates in subjects with low BMD and sarcopenia (Figure 1). Women with low BMD with (HR = 2.80, 95% CI = 1.72–4.58) or without (HR = 3.09, 95% CI = 2.08–4.59) sarcopenia had a risk of fracture that was almost three times as great as that of normal women (Table 3). The effect size decreased to 2.5 in both groups after adjusting for important covariates but remained statistically significant. Women with sarcopenia alone had a fracture rate similar to that of normal women. The interaction term between sarcopenia and low BMD was not statistically significant (P = .37). Low BMD was associated with fracture risk after adjusting for sarcopenia (HR = 3.48, 95% CI = 2.47–4.90), but sarcopenia was not associated with fracture risk after adjusting for low BMD (HR = 1.09, 95% CI = 0.79–1.49). Exclusion of traumatic fractures revealed similar results (Table 3, P-interaction = .38).
Eighty percent of fractures in men and 90% in women involved a fall. In men with low BMD and sarcopenia, 75% of nonspine fractures involved a fall from a standing height or less. Fewer fractures in the other groups (56–64%) involved a fall from a standing height or less (Figure 2A.). Pairwise comparisons showed that differences were statistically significant between men with low BMD and sarcopenia and men with low BMD alone and between men with low BMD and sarcopenia and men without either condition.
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Figure 2.
Proportion of fractures due to a fall from standing height or less according to low bone mineral density (BMD) and sarcopenia in older individuals. (A) The proportion of men with the least degree of trauma was the highest in those with low BMD and sarcopenia. A statistically significant difference was observed for all pairwise comparisons except between sarcopenia alone and low BMD and sarcopenia combined. (B) In women, although the proportion of fractures with the least degree of trauma was the highest in the low BMD and sarcopenia combined group, pairwise comparisons were not statistically significant. Pairwise comparisons were statistically significant between low BMD and low BMD and sarcopenia (P = .03) and between normal and low BMD and sarcopenia combined (P = .03). Shaded = fractures due to falling from less than standing height. Unshaded = fractures due to other circumstances (falling on stairs, steps, or curb; falling from greater than standing height; trauma).
Similarly, in women, a higher proportion of fractures in subjects with low BMD and sarcopenia involved a fall from standing height or less (82%) than of women with low BMD alone (75%), sarcopenia alone (67%), and normal women (78%), although these differences were not statistically significant (Figure 2B).
Results
The majority of men were white, with little difference in race between the groups. Sarcopenic men with or without low BMD were older than those in the other groups, but there was little variability in smoking and alcohol consumption between the groups. A higher percentage of women with low BMD with or without sarcopenia were white, and these women tended to be older. Total hip and femoral neck BMD were the lowest in the low BMD and sarcopenia group in men and in the low BMD with or without sarcopenia groups in women. Unlike sarcopenic women, sarcopenic men had more IADL impairments and more falls.
Men
Eight hundred seventy (16%) men experienced a nonspine fracture (402 (12%) normal; 11 (14%) sarcopenia; 421 (21%) low BMD; 36 (32%) low BMD and sarcopenia). The age-adjusted incidence of nonspine fracture was similar in normal men (13.2/1,000) and those with sarcopenia alone (15.1/1,000) but was much higher in men with low BMD and sarcopenia (46.5/1,000) (Figure 1). Men with low BMD and sarcopenia had a risk of fracture that was almost four times as great as that of normal men (HR= 3.75, 95% CI = 2.64–5.32) (Table 3). Men with sarcopenia alone did not have a statistically significantly higher risk of fractures (HR = 1.19, 95% CI = 0.65–2.17), but the risk of fracture in those with low BMD alone (HR = 1.79, 95% CI = 1.56–2.05) was intermediate between normal men and men with both conditions. These associations remained significant after adjusting for important covariates (Table 3). The interaction term between sarcopenia and low BMD was not statistically significant (P = .06). Low BMD was associated with fracture risk after adjusting for sarcopenia (HR = 1.97, 95% CI = 1.72–2.25). Similarly, sarcopenia was associated with fracture risk after adjusting for low BMD (HR = 2.25, 95% CI = 1.68–3.03). Exclusion of traumatic fractures showed somewhat similar results (Table 3, p-interaction = .11).
(Enlarge Image)
Figure 1.
Age-adjusted incidence rate (per 1,000) of nonspine fractures according to bone mineral density (BMD) and body composition. In men, the incidence rate was the highest for participants with low BMD and sarcopenia. Men with only one or neither condition had lower incidence rates. In women, the incidence rates were similar for participants with low BMD, with or without sarcopenia. Women with neither condition and with sarcopenia alone had lower rates of nonspine fractures.
Women
Two hundred seventy-two (25%) women experienced a nonspine fracture (31 (10%) normal, 7 (15%) sarcopenic, 194 (33%) low BMD, 40 (32%) low BMD and sarcopenia). The age-adjusted incidence of fracture ranged from 13.9 per 1,000 in normal women to approximately 40 per 1,000 in women with low BMD or low BMD and sarcopenia (Figure 1). There was little sex difference in fracture incidence rates in subjects with low BMD and sarcopenia (Figure 1). Women with low BMD with (HR = 2.80, 95% CI = 1.72–4.58) or without (HR = 3.09, 95% CI = 2.08–4.59) sarcopenia had a risk of fracture that was almost three times as great as that of normal women (Table 3). The effect size decreased to 2.5 in both groups after adjusting for important covariates but remained statistically significant. Women with sarcopenia alone had a fracture rate similar to that of normal women. The interaction term between sarcopenia and low BMD was not statistically significant (P = .37). Low BMD was associated with fracture risk after adjusting for sarcopenia (HR = 3.48, 95% CI = 2.47–4.90), but sarcopenia was not associated with fracture risk after adjusting for low BMD (HR = 1.09, 95% CI = 0.79–1.49). Exclusion of traumatic fractures revealed similar results (Table 3, P-interaction = .38).
Circumstances of the Fracture
Eighty percent of fractures in men and 90% in women involved a fall. In men with low BMD and sarcopenia, 75% of nonspine fractures involved a fall from a standing height or less. Fewer fractures in the other groups (56–64%) involved a fall from a standing height or less (Figure 2A.). Pairwise comparisons showed that differences were statistically significant between men with low BMD and sarcopenia and men with low BMD alone and between men with low BMD and sarcopenia and men without either condition.
(Enlarge Image)
Figure 2.
Proportion of fractures due to a fall from standing height or less according to low bone mineral density (BMD) and sarcopenia in older individuals. (A) The proportion of men with the least degree of trauma was the highest in those with low BMD and sarcopenia. A statistically significant difference was observed for all pairwise comparisons except between sarcopenia alone and low BMD and sarcopenia combined. (B) In women, although the proportion of fractures with the least degree of trauma was the highest in the low BMD and sarcopenia combined group, pairwise comparisons were not statistically significant. Pairwise comparisons were statistically significant between low BMD and low BMD and sarcopenia (P = .03) and between normal and low BMD and sarcopenia combined (P = .03). Shaded = fractures due to falling from less than standing height. Unshaded = fractures due to other circumstances (falling on stairs, steps, or curb; falling from greater than standing height; trauma).
Similarly, in women, a higher proportion of fractures in subjects with low BMD and sarcopenia involved a fall from standing height or less (82%) than of women with low BMD alone (75%), sarcopenia alone (67%), and normal women (78%), although these differences were not statistically significant (Figure 2B).
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