Is the association between hip fractures and seasonality modified by influenza vaccination? An ecological study

Exposure to low humidex increases the risk of hip fracture admissions in a subtropical coastal Chinese city

OBJECTIVE

The adverse impacts of meteorological factors on human health have attracted great attention. However, no studies have investigated the nonlinear effects of humidex on hip fractures (HF), particularly in middle-aged and older adults. This study aimed to quantify the impacts of humidex, a comprehensive index of temperature and relative humidity, on HF admissions.

METHODS

Daily HF admissions, meteorological variables and air pollutants in the subtropical coastal city of Shantou, China, from 2015 to 2020 were collected. A generalized linear regression model combined with a distributed lag nonlinear model was applied to explore the exposure-lag-response relationship between humidex and HF admissions. Subgroup analyses were also conducted by gender, age and season. Attributable fractions (AF) and attributable numbers (AN) were used to represent the burden of disease.

RESULTS

A total of 6200 HF admissions were identified during the study period. Taking the median humidex (31.9) as a reference, the single-day lag effects of low humidex (13, 2.5th percentile) were significant at lag 0 [relative risk (RR) = 1.145, 95 % confidence interval (CI): 1.041-1.259] to lag 2 (RR = 1.049, 95 % CI: 1.010-1.089). The cumulative lag effects of low humidex were significant at lag 0-0 (RR = 1.145, 95 % CI: 1.041-1.259) to lag 0-6 (RR = 1.258, 95 % CI: 1.010-1.567) and reached a maximum at lag 0-3 (RR = 1.330, 95 % CI: 1.113-1.590). High humidex (44, 97.5th percentile) was not associated with the risk of HF. Females and people over the age of 75 appeared to be more susceptible to low humidex. In addition, the adverse effects of low humidex were more pronounced in the cold season. The AF and AN of low humidex on HF admissions were 24.8 % (95 % CI: 10.2-37.1 %) and 1538, respectively.

CONCLUSION

Low humidex was associated with an increased risk of HF admissions. The government should take timely measures to prevent people from being exposed to low humidex to effectively reduce HF admissions.

Trend and Seasonality of Hip Fractures in Catalonia, Spain: Exploring the Influence of Climate

To describe the secular trend and seasonality of the incidence of hip fracture (HF) and its relationship with climatic variables during the period 2010-2019 in Catalonia in people aged ≥ 65 years. The results were analyzed by sex, age groups (65-74, 75-84, and ≥ 85), and types of fracture (extracapsular and intracapsular). Data on sex, age, type of fracture, year, and month of hospitalization of patients admitted with a diagnosis of HF between January 1, 2010 and December 31, 2019 were collected. Crude and standardized HF incidence (HFi) rates were obtained. Data on the monthly mean of climatological variables (temperature, insolation, icy days, rain, relative humidity, atmospheric pressure, and wind force) were obtained from the network of meteorological stations in Catalonia. Time series analytical statistics were used to identify trends and seasonality. Linear regression and a seasonal autoregressive integrated moving average (ARIMA) were used to analyze the relationship of each climatic parameter with fracture rates. In addition, generalized additive models were used to ascertain the best predictive model. The total number of HF episodes was 90,149 (74.1% in women and 25.9% in men). The total number of HFs increased by 6.4% between 2010 and 2019. The median age (SD) was 84.5 (7.14) and 54% of patients were ≥ 85 years of age. Extracapsular fractures were the most common (55%). The standardized incidence rates decreased from 728.1/100,000 (95% CI 738.6-769.3) to 624.5/100,000 (95% CI 648.7-677.0), which represents a decrease of 14.2% (p < 0.05). The decline was greater at older ages. There were seasonal variations, with higher incidences in autumn (27.2%) and winter (25.7%) and lower rates in summer (23.5%) and spring (23.6%). Seasonality was more pronounced in elderly people and men. In the bivariate regression analysis, high temperatures and greater insolation were negatively associated with the HF rate, while the number of icy days, rainy days, and high relative humidity were associated with a higher incidence of fractures in all age groups and sexes. In the regression analysis using the seasonal ARIMA model, only insolation had a consistently significant association with overall HFi, after adjusting by trend and other climatic parameters. While the global number of HFs grew in Catalonia due to increases in the elderly population, the standardized HF rate decreased during the years 2010-2019. There was a seasonal trend, with predominance in the cold months and correlations with climatic parameters, especially with insolation.

Association between traffic-related air pollution and osteoporotic fracture hospitalizations in inland and coastal areas: evidences from the central areas of two cities in Shandong Province, China

Our result showed that short-term exposure to traffic-related air pollutants (TRAPs) might increase the risk of hospitalizations for osteoporotic fractures. It was suggested that government should formulate emission reduction policies to protect the health of citizens.

INTRODUCTION

As the main source of urban air pollution in China, exhaust emissions of motor vehicles have been linked to adverse health outcomes, but evidence of the relationship between short-term exposure to TRAPs and osteoporotic fractures is still relatively rare.

METHODS

In this study, a total of 5044 inpatients from an inland city (Jinan) and a coastal city (Qingdao), two cities with developed transportation in Shandong Province, were included. A generalized additive model (GAM) was used to investigate the association between TRAPs and hospitalizations for osteoporotic fractures. The stratified analyses were performed by gender and age.

RESULTS

Positive associations between TRAPs and osteoporotic fracture hospitalizations were observed. We found that short-term exposure to TRAPs was associated with increased numbers of hospitalizations for osteoporotic fractures. PM2.5 and PM10 were statistically significant associated with hospitalizations for osteoporotic fractures at both single-day and multiday lag structures only in Qingdao, with the strongest associations at lag06 and lag07 [RR=1.0446(95%CI: 1.0018,1.0891) for PM2.5, RR=1.0328(95%CI: 1.0084,1.0578) for PM10]. For NO2 and CO, we found significant associations at lag4 in the single lag structure in Jinan [RR=1.0354 (95%CI: 1.0071, 1.0646) for NO2, RR=1.0014 (95%CI: 1.0002, 1.0025) for CO], while only CO at lag4 was significantly associated with hospitalizations for osteoporotic fractures in Qingdao [1.0038 (1.0012, 1.0063)]. Stratified analyses indicated that the associations were stronger in females and older individuals (65 + years).

CONCLUSION

This study implied that short-term exposure to TRAPs pollution was associated with an increased risk of hospitalizations for osteoporotic fractures. Female patients and patients aged 65 + years appeared to be more vulnerable to TRAPs, suggesting that poor air quality is a modifiable risk factor for osteoporotic fractures.

Relationship between meteorological variations, seasonal influenza, and hip fractures in the elderly: A modelling investigation using 22-year data

With the heavy negative health effect and economic burden of hip fractures in the elderly, the relationship of hip fractures with climate and seasonal influenza has not been quantified explicitly. In this study, we aim to make use of population-based data to evaluate the impact of meteorological factors and influenza activity on the hip fracture admissions for the elderly in Hong Kong from 1998 to 2019. Weekly numbers of admissions for the elderly due to hip fractures were used as the study outcome, and were matched with the meteorological factors included air temperature, relative humidity, solar radiation, and total rainfall. Strain-specific influenza-like illness-positive (ILI+) rates were employed as proxies for seasonal influenza activity. Quasi-Poisson generalized additive model in conjunction with distributed-lag non-linear model was used to elucidate the association of interest. According to the results, a total of 191,680 hip fracture admissions for the elderly aged ≥65 years were recorded over a 22-year span. The cumulative adjusted relative risks of hip fracture were 1.35 (95 % CI, 1.26-1.44) at the 5th percentile (15.05 °C) of air temperature, and 1.06 (95 % CI, 1.02-1.10) at the 95th percentile (20.91 MJ/m²) of solar radiation, with the reference value set to their respective medians. ILI+ rates were not associated with the risk of hip fracture. In the stratified analyses, a stronger association between cold condition and hip fracture was observed in males. Based on the results, strategies for preventing hip fractures with a focus on behaviors under unfavorable weather conditions should be targeted at individuals at risk.

The Association of Cold Ambient Temperature With Fracture Risk and Mortality: National Data From Norway-A Norwegian Epidemiologic Osteoporosis Studies (NOREPOS) Study

Norway is an elongated country with large variations in climate and duration of winter season. It is also a high-risk country for osteoporotic fractures, in particular hip fractures, which cause high mortality. Although most hip fractures occur indoors, there is a higher incidence of both forearm and hip fractures during wintertime, compared with summertime. In a nationwide longitudinal cohort study, we investigated whether cold ambient (outdoor) temperatures could be an underlying cause of this high incidence and mortality. Hospitalized/outpatient forearm fractures (International Classification of Diseases and Related Health Problems, 10th Revision [ICD-10] code S52) and hospitalized hip fractures (ICD-10 codes S72.0-S72.2) from 2008 to 2018 were retrieved from the Norwegian Patient Registry. Average monthly ambient temperatures (degrees Celsius, °C) from the years 2008 to 2018 were provided by the Norwegian Meteorological Institute and linked to the residential area of each inhabitant. Poisson models were fitted to estimate the association (incidence rate ratios [IRRs], 95% confidence intervals [CIs]) between temperature and monthly incidence of total number of forearm and hip fractures. Flexible parametric survival models (hazard ratios [HR], 95% CI) were used to estimate the association between temperature and post-hip fracture mortality, taking the population mortality into account. Monthly temperature ranged from -20.2°C to 22.0°C, with a median of -2.0°C in winter and 14.4°C in summer. At low temperatures (<0°C) compared to ≥0°C, there was a 53% higher risk of forearm fracture (95% CI, 51%-55%) and 21% higher risk of hip fracture (95% CI, 19%-22%), adjusting for age, gender, calendar year, urbanization, residential region, elevation, and coastal proximity. When taking the population mortality into account, the post-hip fracture mortality in both men (HR 1.08; 95% CI, 1.02-1.13) and women (HR 1.09; 95% CI, 1.04-1.14) was still higher at cold temperatures. There was a higher risk of forearm and hip fractures, and an excess post-hip fracture mortality at cold ambient temperatures. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Is Cold Apparent Temperature Associated With the Hospitalizations for Osteoporotic Fractures in the Central Areas of Wuhan? A Time-Series Study

Osteoporosis is alarming problem due to aggravation of global aging, especially in China. Osteoporotic fracture (OF) is one of the most severe consequents of osteoporosis. Many previous studies found that environmental factors had adverse effects on human health. Cold temperature was associated with OF and bone metabolism in prior observational and experimental researches. However, few studies had been conducted on the acute effect of low temperature and OF. Data on daily meteorological factors and hospitalizations for OF were collected from Wuhan, China, between January 1, 2017 to December 24, 2019. Apparent temperature (AT), comprehensively considered a variety of environmental factors, was calculated by ambient temperature, relative humidity and wind speed. A generalized linear regression model combined with distributed lag non-linear regression model (DLNM) with quasi-Poisson link was used to explore the association between AT and the number of hospitalizations for OF. Subgroup analyses stratified by gender, age and the history of fracture were applied for detecting susceptible people. The exposure-response curve of AT and OF were generally U-shaped with lowest point at 25.8°C. The significant relationship of AT-OF existed only in cold effect (-2.0 vs. 25.8°C) while not in warm effect (37.0 vs. 25.8°C). Statistically significant risks of OF for cold effects were only found in females [RR = 1.12 (95%CI: 1.02, 1.24) at lag 2 day], aged <75 years old [RR = 1.18 (95%CI: 1.04, 1.33) and 1.17 (95%CI: 1.04, 1.33) at lag 2 and 3 days, respectively] and people with history of fracture [RR = 1.39 (95%CI: 1.02, 1.90) and 1.27 (95%CI: 1.05, 1.53) at lag 1 and 2 days, respectively]. The significant associations of AT on OF were only found in cold effect. The females, people aged <75 years and people with history of fracture possibly appeared to be more vulnerable. Public health departments should pay attention to the negative effect of cold AT and take measures in time.

Association of ambient temperature and sun exposure with hip fractures in Japan: A time-series analysis using nationwide inpatient database

BACKGROUND

Evidence on whether meteorological conditions affect hip fractures (HFs) is limited. This study aimed to clarify the associations between ambient temperature and sun exposure and HFs in Japan.

METHODS

Record of daily hospital admissions for HFs between 2015 and 2018 were extracted from a Japanese nationwide inpatient database. We conducted a time-series quasi-Poisson regression analysis using a distributed lag non-linear model with lag 0-39 days to estimate prefecture-specific relative risks (RRs) of HFs. We also estimated pooled RRs using random-effects meta-analysis.

RESULTS

We identified 355,563 HFs. For mean temperature, immediate RRs (lag 0-2 days) were 1.349 (95% confidence interval (CI): 1.305, 1.395) and 0.754 (95% CI: 0.727, 0.782) for low (mean of the 2.5th percentile) and high (mean of the 97.5th percentile) mean temperature, respectively, relative to the reference (mean of medians). For sunshine duration, immediate RRs were 0.929 (95% CI: 0.913, 0.946) and 1.056 (95% CI: 1.029, 1.085) for short (mean of the 2.5th percentile) and long (mean of the 97.5th percentile) sunshine duration, respectively, and delayed RRs (lag 3-39 days) was 0.770 (95% CI: 0.696, 0.851) for long sunshine duration relative to the reference (mean of medians). Immediate RRs were larger for both exposures in patients admitted from home than in those from care facilities.

CONCLUSIONS

Lower mean temperature and longer sunshine duration were associated with immediate higher HF risks. Higher mean temperature and shorter sunshine duration were associated with immediate lower HF risks. These associations were modified by admission routes. Longer sunshine duration was also associated with delayed lower HF risks.

Fractures and fall injuries after hospitalization for seasonal influenza-a national retrospective cohort study

In this retrospective cohort study of 6604 adults, 65 years or older, admitted with seasonal influenza at Swedish hospitals, and 330,200 age- and sex-matched controls from the general population admitted for other reasons, were included. Patients with influenza had increased risk of fall injuries and fractures compared to controls.

INTRODUCTION

Fractures and fall injuries often lead to disability, increased morbidity, and mortality. Older adults are at higher risk of influenza-related complications such as pneumonia, cardiovascular events, and deaths, but the risk of fractures and fall injuries is unclear. The primary objective of this study was to investigate the risk of fractures and fall injuries in older patients after admission with seasonal influenza.

METHODS

In this retrospective cohort study of 6604 adults, 65 years or older, admitted with seasonal influenza at Swedish hospitals (from December 1, 2015, to December 31, 2017) and 330,200 age- and sex-matched controls from the general population and admitted for other reasons, the risk of fracture or fall injury was investigated.

RESULTS

The mean (SD) age of the 6604 influenza patients was 80.9 (8.1) years and 50.1% were women. During the first year after hospital discharge, there were 680 (10.3%) patients suffering from a fracture or fall injury among the patients with influenza, and 25,807 (7.8%) among the controls, corresponding to incident rates of 141 (95% CI, 131-152) and 111 (95% CI, 110-112) fractures or fall injuries per 1000 person-years respectively, translating to a significantly increased risk of fracture or fall injury in a Cox regression model (hazard ratio (HR) 1.28 (95% CI, 1.19-1.38)), a risk that was maintained after multivariable adjustment (HR 1.22 (95% CI 1.13-1.31)).

CONCLUSIONS

Older adults admitted with influenza diagnosis have an increased risk of fracture or fall injury during the first year after discharge.

The disease burden of influenza beyond respiratory illness

Although influenza is primarily considered a respiratory infection and causes significant respiratory mortality, evidence suggests that influenza has an additional burden due to broader consequences of the illness. Some of these broader consequences include cardiovascular events, exacerbations of chronic underlying conditions, increased susceptibility to secondary bacterial infections, functional decline, and poor pregnancy outcomes, all of which may lead to an increased risk for hospitalization and death. Although it is methodologically difficult to measure these impacts, epidemiological and interventional study designs have evolved over recent decades to better take them into account. Recognizing these broader consequences of influenza virus infection is essential to determine the full burden of influenza among different subpopulations and the value of preventive approaches. In this review, we outline the main influenza complications and societal impacts beyond the classical respiratory symptoms of the disease.

The immune response to influenza in older humans: beyond immune senescence

Despite widespread influenza vaccination programs, influenza remains a major cause of morbidity and mortality in older adults. Age-related changes in multiple aspects of the adaptive immune response to influenza have been well-documented including a decline in antibody responses to influenza vaccination and changes in the cell-mediated response associated with immune senescence. This review will focus on T cell responses to influenza and influenza vaccination in older adults, and how increasing frailty or coexistence of multiple (≥2) chronic conditions contributes to the loss of vaccine effectiveness for the prevention of hospitalization. Further, dysregulation of the production of pro- and anti-inflammatory mediators contributes to a decline in the generation of an effective CD8 T cell response needed to clear influenza virus from the lungs. Current influenza vaccines provide only a weak stimulus to this arm of the adaptive immune response and rely on re-stimulation of CD8 T cell memory related to prior exposure to influenza virus. Efforts to improve vaccine effectiveness in older adults will be fruitless until CD8 responses take center stage.

Meteorological variables and the risk of fractures: A systematic review and meta-analysis

PURPOSE

The association between meteorological variables and risk of fractures has attracted increasing attentions but remain controversial. Therefore, our main aim is to clarify the association, and also to identify possible susceptible groups.

METHODS

Relevant literature was obtained through standard MeSH literature searching seven electronic databases. Because some studies expressed the association as the rate of incidence (IRR) of fractures associated with each 1 °C rise in temperature and 1% increase in relative humidity (RH), some expressed as IRR of fractures for the day with specific climatic variable versus control days, and also the association was expressed as correlations coefficients (COR) in some studies, separated meta-analyses were undertaken, with one based on IRR and another based on COR.

RESULTS

A total of 24 studies were included. Results showed that each 1 °C increase was significantly associated with a 3.0% decrease in fracture risk (IRR = 0.970, 95%CI: 0.952-0.988). The day with freezing rain and snow were associated with increased risk for both the lower extremity fracture (freezing rain: IRR = 1.174, 95%CI: 1.022-1.348; snow: IRR = 1.245, 95%CI: 1.050-1.477) and the upper extremity fracture (freezing rain: IRR = 1.376, 95%CI: 1.192-1.588; snow: IRR = 1.548, 95%CI: 1.361-1.761). No significant association was detected between RH, dew, frost, fog, storm and high wind, and fracture. The COR meta-analysis showed that mean temperature (moderately), maximum temperature (moderately), rainfall (weakly) and sunlight duration (weakly) were correlated with fracture occurrence.

CONCLUSION

The incidence of fractures was increased in lower temperature, the day with freezing rain, and snow. Other meteorological factors may have some effects on the incidence of fracture. The association maybe stronger for males, lower extremity fracture, and people living in Asia, subtropical zone, low-latitude, and northern hemisphere. Further studies are needed.

Influenza Illness and Hip Fracture Hospitalizations in Nursing Home Residents: Are They Related?

Background

Influenza illness may impact the risk of falls and fractures during acute illness due to unsteady gait or dizziness. We evaluated the association between influenza and hip fracture hospitalizations in long-stay (LS) nursing home (NH) residents.

Methods

We analyzed weekly rates of hospitalization in a retrospective cohort of LS NH residents between January 1, 2000 to December 31, 2009. Hip fracture and influenza like illness (ILI) hospitalizations were identified with Medicare fee-for-service part A claims. We evaluated unadjusted and adjusted models with the primary exposures, weekly rate of influenza-like illness hospitalizations, city-wide mortality, and NH influenza vaccination rate and primary outcome of weekly rate of hip fracture hospitalizations.

Results

There were 9,237 incident hip fractures in the cohort. Facility wide ILI hospitalization rate was associated with the hip fracture hospitalization rate in the unadjusted (incidence rate ratio [IRR] 1.13, 95% confidence interval [CI]: 1.08, 1.17) and adjusted (IRR 1.13, 95% CI: 1.09, 1.18) analyses. City-wide influenza mortality was associated with hip fracture hospitalization rates for the unadjusted (IRR 1.03, 95% CI: 1.02, 1.04), and adjusted (IRR 1.02, 95% CI: 1.01, 1.03) analyses. NH influenza vaccination rates were not associated with changes in hip fracture hospitalization rates.

Conclusions

ILI hospitalizations are associated with a 13% average increase in hip fracture hospitalization risk. In a given NH week, an increase in the number ILI hospitalizations from none to two was associated with an approximate one percentage point increase in hip fracture hospitalization risk. Strategies to reduce influenza risk should be investigated to reduce hip fracture risk.