Prevalence Characteristics of Osteoporosis Fractures in the Elderly in Two Regions of China and Analysis of the Lag Effect of Air Pollutants on them

Abstract

Objective: Air pollution is increasing and threatening human health. The objective of this study is to investigate the population distribution characteristics of elderly osteoporosis fractures in Hebei Province and Xinjiang Uygur Autonomous Region and to analyze the effects of air pollutants on the number of elderly osteoporosis fracture inpatients in the two regions.

Method: A retrospective collection of elderly osteoporosis fracture cases was conducted in selected hospitals in Hebei Province and Xinjiang Uygur Autonomous Region from January 1, 2018 to December 31, 2022. The chi-square test was used to compare the distributional characteristics of the population in the two regions. Additionally, we used a distributed lag nonlinear model (DLNM) in order to assess the effect of air pollutants on the number of daily hospital admissions of elderly osteoporosis fracture patients in different regions.

Result: A total of 19,203 elderly osteoporosis fracture patients were included in the study. The average age of these patients was 76.66 ± 7.55 years, and the majority of them were female (13,514 instances, 70.37%). The disparities in age distribution (χ² = 133.9 p < 0.001), fracture site (χ² = 62.0 p < 0.001), and hospitalization cost (Z = -15.635 p < 0.001) between the two regions were statistically significant. The lag effect curves of PM2.5, PM10, and NO₂ on the number of elderly osteoporosis fracture hospitalizations in Xinjiang Uygur Autonomous Region exhibited a similar pattern resembling a "W"-shaped curve. All three pollutants reached their highest values after a lag time of 14 days (PM2.5: RR = 1.053, 95% CI: 1.031, 1.074; PM10: RR = 1.031, 95% CI: 1.018, 1.043; NO₂: RR = 1.125, 95% CI: 1.070, 1.182). In Hebei Province, the largest impacts of PM2.5 and PM10 were observed after a lag of 14 days (PM2.5: RR = 1.022, 95% CI: 1.013, 1.028; PM10: RR = 1.013, 95% CI: 1.008, 1.018). Similarly, the maximum effect of NO₂ was observed after a lag of 11 days (RR = 1.020, 95% CI: 1.010, 1.028).

Conclusion: There were differences in the epidemiological characteristics of hospitalized patients with osteoporosis fractures between the two regions, PM2.5, PM10, and NO₂ increased the number of hospitalizations for osteoporosis fractures. Exposure to air pollutants such as PM2.5 increases the risk of osteoporosis fractures in the elderly population.

Keywords: Air Pollutants; Distributed Lag Nonlinear Model; Epidemiological Features; Osteoporosis Fractures in the Elderly.

Fig. 1

Trend of elderly osteoporosis hospitalized patients in Hebei Province and Xinjiang Uygur Autonomous Region, 2018–2022. The number of elderly osteoporosis fracture patients in Hebei province has been increasing yearly, the number of elderly osteoporosis fracture patients in Xinjiang increased yearly since 2018, reached the peak in 2021, and then began to decline.

Fig. 2

Trend of monthly average elderly osteoporosis hospitalized patients in Hebei Province and Xinjiang Uygur Autonomous Region. The average number of reported cases was highest in October and lowest in February in Hebei province, the average number of reported cases was highest in May and lowest in February in Xinjiang.

Fig. 3

Sex ratio of elderly osteoporosis fracture patients in Hebei Province (A) and Xinjiang Uygur Autonomous Region (B). The majority of patients with osteoporosis fractures in both regions were female.

Fig. 4

Age distribution of elderly osteoporosis bone patients in Hebei Province (A) and Xinjiang Uygur Autonomous Region (B). The patients with osteoporosis fractures in Hebei Province are mainly in 65–74 years age group, the patients with osteoporosis fractures in Xinjiang are mainly in 75–84 years age group.

Fig. 5

Distribution of fracture sites in elderly osteoporosis fracture patients in Hebei Province (A) and Xinjiang Uygur Autonomous Region (B). Among the elderly osteoporosis fracture patients in Hebei Province, hip fracture accounted for the highest proportion, followed in the order of vertebral fracture, distal radius fracture, and proximal humerus fracture, among the elderly osteoporosis fracture patients in Xinjiang, hip fracture accounted for the highest proportion, followed by vertebral fracture, distal radius fracture, and proximal humerus fracture.

Fig. 6

Single‐day lagged effects between inpatient visits for elderly osteoporosis fractures and air pollutants in Xinjiang Uygur Autonomous Region. Single‐day lagged effects between inpatient visits for elderly osteoporosis fractures and PM2.5 (A), PM10 (B), and NO₂ (C) in Xinjiang Uygur Autonomous Region. The green curve is the RR value for the different lag days, and the shaded part is the 95% confidence interval.

Fig. 7

Contour plots illustrating single‐day lagged associations between inpatient visits for elderly osteoporosis fractures and air pollutants in Hebei Province Contour plots illustrating single‐day lagged associations between inpatient visits for elderly osteoporosis fractures and PM2.5 (A), PM10 (B), NO₂ (C), and SO₂ (D) in Hebei Province. The abscissa is the concentration of the pollutant, the ordinate is the number of lag days, and the different colors represent RR values for different concentrations of air pollutants and for different lag days.