For older women, the majority of hip fragility fractures and radiographic vertebral fragility fractures occur among the densitometrically osteoporotic population: a literature analysis

Abstract

It has been frequently cited that 'the majority of fragility fractures (FF) occur at non-osteoporotic bone mineral density (BMD)'. For the reports with T-score measured around the time of a hip fracture, we conducted a systematic literature search in December 2022, and resulted in 10 studies with five for Caucasian women and five for East Asian women. Femoral neck (FN) T-score was reported in five Caucasian studies and three East Asian studies, three of five Caucasian studies had a mean T-score ≤-2.5, and one study had the majority of their patients measuring a mean T-score ≤-2.5. All three East Asian studies reported a mean FN T-score ≤-2.7. Total hip T-score was reported in two Caucasian studies and three East Asian studies, the two Caucasian studies both had a mean T-score ≤-2.5, and all three East Asian studies had a mean T-score ≤-2.6. A new literature search conducted in April 2024 results in additional three studies, with results being consistent with the data described above. A trend was noted that 'younger' patients suffer from hip fractures at a 'higher' T-score. For the highly cited articles where the notion the majority of FF occur at non-osteoporotic BMD was derived from, authors reported prospective epidemiological studies where BMD was not measured at the timepoint of hip fracture, instead, BMD was measured at the study baseline. These epidemiological studies suggest that >50% of hip fractures likely occur in women with an osteoporotic FN or hip T-score. However, a pattern was seen that older men suffer from hip fracture at a notably higher T-score than older women. For the cases of radiographic vertebral FF, despite varying criteria being used to classify these FFs, the majority of female patients had spine densitometric osteoporosis. Literature shows, compared with the cases of hip fracture, distal forearm fracture occurs at a 'younger' age and 'higher' BMD, suggesting distal forearm fracture is more likely associated with a 'higher' trauma energy level.

Keywords: Bone mineral density (BMD); hip fracture; osteoporosis; osteoporotic vertebral fracture; prevalence.

Figure 1

Distribution of T-scores of female patients with proximal femur fracture. Caucasian data in green color, East Asian data in pink color. (A) FN data, (B) TH data. A1: Wilson et al. (10); A2: Olszewski et al. (11); A3: Schnabel et al. (12); A4 and B1: Di Monaco et al. (13); A5 and B2: Yeo et al. (14); A6: Lee et al. (15); A7 and B5, [Gani et al. (16), non-diabetic group n=350, though the title of the article suggests only patients with severe osteoporotic hip fracture, however, according to the methodology and the T-score values, they included all low energy hip fracture patients]; A8: Zhu et al. (17); B3, Ho et al. (18); B4: Li et al. (19). In the study of Olszewski et al.; in total there were 37 patients, and the patients were divided into three age groups: <69 years (n=4, T-score =−1.5±0.68), 70–79 years (n=10, T-score =−1.3±0.38), and >80 years (n=23, T-score =−2.7±0.82). FN, femoral neck; TH, total hip.

Figure 2

A comparison of FN or TH T-score of female patients and male patients. (A) Acute proximal femur fracture cases. Data are from Wilson et al. (10), Yeo et al. (14), Lee et al. (15), Gani et al. (16), Ho et al. (18); Li et al. (19), and Vlachos et al. (21). This graph was initially presented in (9). Except the data of Wilson et al., all other six groups’ data show a higher FN or TH T-score in men than in women. Yeo et al. and Gani et al. also presented TH T-score, with a similar trend shown in this graph. Arrow: male patients were younger in 4 out of 6 studies. Caucasian data in green color and East Asian data in pink color. (B) MrOS and MsOS Hong Kong studies. These are prospective studies with FN T-score measured at baseline. One thousand and nine hundred Chinese women (baseline age: 72.5 years) were followed up for 8.82±1.49 years, and 69 hip fracture were recorded. One thousand nine hundred and twenty-three Chinese men (baseline age: 72.3 years) were followed up for 9.94±2.77 years, and 63 hip fracture were recorded. The mean baseline T-score for the men with hip fracture during the follow-up was 0.61 higher than that of women with hip fracture during follow-up (blue line with double arrow heads). The mean age fracture was 82.5 years for men and 82.0 years for women. Therefore, a pattern was seen that older men suffer from hip fracture at a notably higher T-score (about 0.5–0.6 higher) than older women. The reason for this trend could be due to (I) male patients were involved with a ‘higher’ trauma energy level, (II) male patients tended to be younger in the study listed in graph (A); (III) osteoporosis T-score threshold for male patients should be defined higher than that of female patients. TH, total hip; FN, femoral neck; MrOS, Osteoporotic Fracture in men; MsOS, Osteoporotic Fracture in women; FF, fragility fractures; FU, follow-up.

Figure 3

Compared with cases with hip fracture, distal forearm fracture is more likely associated with a ‘higher’ trauma energy level. (A) A standing person; (B,C) a fall will lead to a distal forearm (wrist) hitting the ground; (D) a fall will lead to a buttock hitting the ground. The net external force equals the change in momentum of a system divided by the time over which it changes. If we assume that the angular velocity is the same for a forward fall (B,C) as for a backward fall (D), since the radius r1>r2, velocity at the impact with the ground for a forward fall (v1) will be larger than that for a backward fall (v2, v1>v2) (E). In addition, due to the buffering of muscle and fat at the buttock, the impact time for backward fall (t2) will be larger than that of forward fall (t, t1

Figure 4

The correlation between OLVFss and femoral neck T-score (A) or lowest T-score of femoral neck, total hip, or lumbar spine T-scores (B). In A, radiographic vertebral FF is statistically diagnosed when OLVFss is ≤−1.5. Approximately 55.6% of the vertebral FF cases have femoral neck densitometric osteoporosis. In B, radiological vertebral FF is statistically diagnosed when OLVFss is ≤−1.0. 71.1% of the vertebral FF cases have densitometrical osteoporosis considering the lowest T-score. Of 301 women, 80 cases had DXA densitometric osteoporosis according to femoral neck T-score ≤−2.5, among them 85% (68/80) had OLVFss ≤−1.0, and 75% (60/80) had OLVFss ≤−1.5. Moreover, 135 cases had densitometric osteoporosis according to the lowest T-score ≤−2.5, among them 71% (96/135) had OLVFss ≤−1.0, and 62.2% (84/135) had OLVFss ≤−1.5. Data from Wáng et al. (42), with in total 301 Italian community Caucasian women (mean age: 73.6±6.1 years). OLVFss, osteoporotic-like vertebral fracture sum score; FF, fragility fractures; DXA, dual-energy X-ray absorptiometry.

Figure 5

The majority of older women with radiographic VFF are densitometrically osteoporotic for lumbar spine. (A) A German prospective study of 84 patients aged 50 years and older (67 being female, mean age unspecified but likely to be around 70 years, assumed predominantly Caucasians). Over a median follow-up of 2.6 years, 16 (19%) sustained an incident VFF. Patients with incident VFF had a lower mean QCT spine BMD of 56.7±31.6 mg/mL than patients without incident VFF with a mean QCT spine BMD of 93.3±41.7 mg/mL. (B) An Italian cross-sectional study of 304 postmenopausal women (age 58.8±5.5 years). Subject with VFF had a spine DXA BMD of 0.724±0.098 g/cm², while those without VF had a BMD of 0.951±0.103 g/cm². Red squares denote the threshold to diagnose spine osteoporosis (0.774 g/cm²), and green dot denotes the population mean for older Italian women (43). All data in B refer to Hologic scanners. (C) For spine DAX measure and (D) for spine QCT measure are from one cross-sectional study of French Caucasian women. (C) shows 61.4% of the subjects with VFF are in the DXA osteoporotic range, while 38.6% are not in DXA osteoporotic range. The threshold to diagnose osteoporosis is also considered to be 0.774 g/cm² (Hologic scanner, 50). (D) shows 87.8% of the subjects with VFF are in the QCT spine osteoporotic range, while 12.2% are not in QCT spine osteoporotic range. (E) is an UK cross-sectional case-control study for age-matched postmenopausal women with and without VFF (assumed predominantly Caucasians). G1: subjects (n=39, mean: 68.9 years) with low DXA BMD (T-score ≤−1) plus with VFF. G2: subjects (n=34, mean: 69.9 years) with low DXA BMD without VFF. G3: subjects (n=37, mean: 68.9 years) with normal DXA BMD without VFF. (F) is a study of a mixed-sex group of 88 German men and women (the majority being female, mean age unspecified but likely to be around 70 years, assumed predominantly Caucasians). 69 patients had VFF (G1), and 19 patients did not have VFF (G2). (G) 91 Japanese women of varying ages, with 20 of them having VFF. (H) Chinese women with VFF (G1, n=198, age mean: 68.0 years; range, 61.0–75.0 years) and sex- and age-matched controls without VFF (G2, n=198). For Caucasian women, the spine QCT threshold to classify osteoporosis is 80 mg/mL. For East Asian women, a threshold of 45 mg/mL is used to classify osteoporosis. Results of (A,B,E,F) are expressed as mean and standard deviation. Results of (H) are expressed as mean and ranges. German data-1 (A) re-plotted from Löffler et al. (44). Italian data (B) re-plotted from Gonnelli et al. (45). French data (C,D) re-plotted from Bergot et al. (46). UK data (E) re-plotted from Paggiosi et al. (47). German data-2 (F) re-plotted from Sollmann et al. (48). Japanese data (G) re-plotted from Fujii et al. (49). Chinese data (H) re-plotted from Mao et al. (50). QCT, quantitative computed tomography; VFF, vertebral fragility fracture; BMD, bone mineral density; DXA, dual-energy X-ray absorptiometry.