Cause-specific excess mortality after hip fracture: the Norwegian Epidemiologic Osteoporosis Studies (NOREPOS).

BACKGROUND: Information on cause of death may help appraise the degree to which the high excess mortality after hip fracture reflects pre-existing comorbidities or the injury itself. We aimed to describe causes of death and cause-specific excess mortality through the first year after hip fracture. METHODS: For studying the distribution of causes of death by time after hip fracture, we calculated age-adjusted cause-specific mortality at 1, 3, 6 and 12 months in patients hospitalized with hip fracture in Norway 1999-2016. Underlying causes of death were obtained from the Norwegian Cause of Death Registry and grouped by the European Shortlist for Causes of Death. For estimating excess mortality, we performed flexible parametric survival analyses comparing mortality hazard in patients with hip fracture (2002-2017) with that of age- and sex matched controls drawn from the Population and Housing Census 2001. RESULTS: Of 146,132 Norwegians with a first hip fracture, a total of 35,498 (24.3%) died within one year. By 30 days post-fracture, external causes (mainly the fall causing the fracture) were the underlying cause for 53.8% of deaths, followed by circulatory diseases (19.8%), neoplasms (9.4%), respiratory diseases (5.7%), mental and behavioural disorders (2.0%) and diseases of the nervous system (1.3%). By one-year post-fracture, external causes and circulatory diseases together accounted for approximately half of deaths (26.1% and 27.0%, respectively). In the period 2002-2017, cause-specific one-year relative mortality hazard in hip fracture patients vs. population controls ranged from 1.5 for circulatory diseases to 2.5 for diseases of the nervous system in women, and correspondingly, from 2.4 to 5.3 in men. CONCLUSIONS: Hip fractures entail high excess mortality from all major causes of death. However, the traumatic injury of a hip fracture is the most frequently reported underlying cause of death among older patients who survive less than one year after their fracture.

Characteristics of fallers who later sustain a hip fracture: a NOREPOS study.

Fall prevention programs have shown inconclusive results concerning hip fracture reduction. We found that fallers with poor health, low societal participation, and use of psychotropics/painkillers had a threefold to fivefold increased hip fracture risk compared to non-fallers without these risk factors. This may help target fall prevention towards high-risk individuals. INTRODUCTION: To investigate whether self-reported information on health, societal participation, and drug use in older people, easily obtainable by health care providers, contribute to predict future hip fracture beyond self-reported falls. METHODS: We used data from 3801 women and 6439 men aged 70-79 years participating in population-based studies in five counties in Norway 2000-2003. Height and weight were measured. Socioeconomic status, lifestyle, health status, and history of falling were self-reported through questionnaires. Falls last year were dichotomized into one or more versus no falls. Hip fractures were identified by linkage to hospital data with follow-up through 2013. Hazard ratios (HR) with 95% confidence intervals (95% CI) for hip fracture by combinations of risk factors with history of falling were estimated using Cox proportional hazards regression. RESULTS: More women (32.4%) than men (27.7%) reported one or more falls during the previous year, and 17.9% of women (n = 682) and 8.9% of men (n = 572) suffered a hip fracture during median 11.6 years of follow-up. Poor health, low societal participation, and use of psychotropics/analgesics among fallers were strong predictors of hip fracture. The presence of all three risk factors and history of falling was associated with HR 2.92 (95% CI 2.10-4.05) for hip fracture in women and HR 4.60 (95% CI 2.71-7.81) in men compared to non-fallers without these factors. CONCLUSION: Our study indicates that self-assessment of health, information about activities outside home, and drug use among fallers far better identify high risk of hip fracture in older people than information about falls alone.

Impact of Total Hip Replacements on the Incidence of Hip Fractures in Norway During 1999-2019. A Norwegian Epidemiologic Osteoporosis Studies (NOREPOS) Study.

The knowledge about why hip fracture rates in Norway have declined is sparse. Concurrent with decreasing hip fracture rates, the rates of total hip replacements (THRs) have increased. We wanted to investigate if hip fracture rates continued to decline, and whether the increase in THRs had any influence on this decline, assuming that living with a hip prosthesis precludes fracture of the operated hip. Information on hip fractures in Norway 1999-2019 was available from the Norwegian Epidemiologic Osteoporosis Studies (NOREPOS) hip fracture database and population size were available in official population tables from Statistics Norway. Primary THRs (for any cause except hip fracture) 1989-2019 were obtained from the Norwegian Arthroplasty Register. We calculated the annual age-standardized incidence rates of hip fracture by sex for the period 1999-2019. The hip fracture rates in a scenario with no hip prostheses were calculated by subtracting 0.5 persons from the population at risk for each prevalent hip prosthesis, considering that each person has two hips at risk of fracture. We estimated how much of the decline could be attributed to the increased prevalence of hip prostheses. From 1999 to 2019, age-standardized incidence rates of hip fracture decreased by 27% in women and 20% in men. The rates remained stable in those under 70 years and decreased in those 70 years and above. Excluding replaced hips from the population at risk led to higher incidence rates, and this impact was considerably larger at higher ages. The increased prevalence of hip prostheses over the period accounted for approximately 18% (20% in women and 11% in men) of the observed decline in hip fracture rates. In conclusion, the incidence of hip fractures continued to decline, and the increasing number of people living with hip prostheses contributed significantly to the observed declining time trends. © 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).

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).

Increased Mortality in Hip Fracture Patients Living Alone: A NOREPOS Study.

Hip fracture is associated with excess mortality, persisting for many years after the fracture. Several factors may affect survival; however, the role of social support has been less studied. Living situation could be an indicator of a person's social support, which predicts mortality in the general population. In this longitudinal cohort study, we considered whether living alone was a risk factor for post-hip fracture mortality compared with living with a partner. Information on hip fractures from all hospitals in Norway from 2002 to 2013 was combined with the 2001 National Population and Housing Census. The association between living situation and mortality during 12.8 years of follow-up in 12,770 men and 22,067 women aged 50 to 79 years at fracture was investigated using flexible parametric survival analysis. We also estimated relative survival of hip fracture patients compared with that of the non-fractured background population in the same living situation (alone or with a partner). Higher mortality after hip fracture was found in both men and women living alone versus with a partner (hazard ratio [HR] men = 1.37, 95% confidence interval [CI] 1.29-1.44; HR women = 1.23, 95% CI 1.18-1.28, adjusting for age, education level, urbanization degree, and number of children). We demonstrated the strongest association in male hip fracture patients aged <60 years (long-term mortality HR = 3.29, 95% CI 2.25-6.49). Compared with the general population, relative survival 8 years after a hip fracture was 43% in men and 61% in women living alone, whereas relative survival in those living with a partner was 51% in men and 67% in women. In conclusion, hip fracture patients who lived alone had higher mortality than those living with a partner and lower survival relative to the general population. © 2021 American Society for Bone and Mineral Research (ASBMR).

Milk drinking and risk of hip fracture: the Norwegian Epidemiologic Osteoporosis Studies (NOREPOS).

Milk provides energy and nutrients considered protective for bone. Meta-analyses of cohort studies have found no clear association between milk drinking and risk of hip fracture, and results of recent studies are contradictory. We studied the association between milk drinking and hip fracture in Norway, which has a population characterised by high fracture incidence and a high Ca intake. Baseline data from two population-based cohorts were used: the third wave of the Norwegian Counties Study (1985-1988) and the Five Counties Study (2000-2002). Diet and lifestyle variables were self-reported through questionnaires. Height and weight were measured. Hip fractures were identified by linkage to hospital data with follow-up through 2013. Of the 35 114 participants in the Norwegian Counties Study, 1865 suffered a hip fracture during 613 018 person-years of follow-up. In multivariable Cox regression, hazard ratios (HR) per daily glass of milk were 0·97 (95 % CI 0·92, 1·03) in men and 1·02 (95 % CI 0·96, 1·07) in women. Of 23 259 participants in the Five Counties Study, 1466 suffered a hip fracture during 252 996 person-years of follow-up. HR for hip fractures per daily glass of milk in multivariable Cox regression was 0·99 (95 % CI 0·92, 1·07) in men and 1·02 (95 % CI 0·97, 1·08) in women. In conclusion, there was no overall association between milk intake and risk of hip fracture in Norwegian men and women.

Homocysteine-Lowering Treatment and the Risk of Fracture: Secondary Analysis of a Randomized Controlled Trial and an Updated Meta-Analysis.

High plasma homocysteine is a risk factor for osteoporotic fractures. Several studies have assessed the possible preventive effect of homocysteine-lowering B-vitamin treatment on the risk of fracture with inconclusive results. In the current study, we include new results from the Aspirin Folate Polyp Prevention Study (AFPPS) together with an updated meta-analysis of randomized controlled trials (RCTs). Our objective was to determine whether there is an association between homocysteine-lowering B-vitamin treatment and the risk of fracture. The AFPPS trial was performed between 1994 and 2004 in nine clinical centers in the United States, and 1021 participants were randomized to a daily folic acid dose of 1 mg (n = 516) or placebo (n = 505). The main outcome was fracture of any type. In addition, we analyzed the risk of hip fracture. In the meta-analysis, studies were identified following a search strategy in electronic database and by hand searching. Risk ratio with 95% confidence interval (CI) was chosen for pooled analyses. In the AFPPS, no statistically significant association was found between folic acid treatment and fractures of any type (risk ratio [RR] = 0.95; 95% CI 0.61-1.48) or hip fracture (RR = 0.98; 95% CI 0.25-3.89). In the meta-analysis, six RCTs were included with a total of 36,527 participants. For interventions including folic acid and/or vitamin B12, the pooled RR for treatment was 0.97 (95% CI 0.87-1.09) for fractures of any type (n = 1199) and 1.00 (95% CI 0.81-1.23) for hip fractures (n = 335). In conclusion, no association was found between homocysteine-lowering treatment with B vitamins (folic acid and vitamin B12) and the risk of fracture. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Does the Association of Comorbidity with 1-Year Mortality After Hip Fracture Differ According to Gender? The Norwegian Epidemiologic Osteoporosis Studies (NOREPOS).

BACKGROUND/OBJECTIVES: Excess mortality after hip fracture is higher in men than in women. The objective was to study whether comorbidity differs in men and women with hip fracture and to what degree differences in comorbidity according to gender may explain the higher excess mortality in men. DESIGN: Population-based matched cohort covering the population aged 50 and older in Norway. SETTING: Specialist healthcare (individuals with hip fracture) and general population (controls). PARTICIPANTS: All individuals with hip fracture aged 50 and older from 2005 to 2008 (n = 32,175) and individuals without hip fracture matched 3:1 to those with hip fracture on gender, age, and county of residence (n = 96,410). MEASUREMENTS: Comorbid diagnoses were recorded during the hospital stay. Relative and absolute excess 1-year mortality in individuals with hip fracture according to gender and Charlson Comorbidity Index (CCI) were investigated using Cox regression and linear regression, respectively. RESULTS: Despite lower age (mean 78.7 vs 81.7), men had higher comorbidity than women. Compared with controls, women (hazard ratio (HR) = 6.5, 95% confidence interval (CI) = 6.2-6.9) and men (HR = 7.8, 95% CI = 7.3-8.3) with a CCI of 2 or greater were more likely to die. Women with a CCI of 2 or greater had an estimated 1-year risk of dying of 44%, and controls had an 11% risk; men with a CCI of 2 or greater had an estimated risk of dying of 53%, and controls had a 12% risk. Men were twice as likely as women to die within 1 year (HR = 2.0, 95% CI = 1.9-2.1). When adjusting for comorbidity, the difference was only slightly smaller (HR = 1.8, 95% CI = 1.7-1.8). CONCLUSION: Men had greater comorbidity than women, but this did not explain the difference according to gender in excess mortality after hip fracture. Men who fracture a hip are an especially vulnerable subpopulation, even when there is no apparent comorbidity, and warrant special attention in follow-up and care.

Age and Sex Differences in Body Mass Index as a Predictor of Hip Fracture: A NOREPOS Study.

It is unclear whether very high body mass index (BMI; weight (kg)/height (m)2) lowers risk of hip fracture. Our objectives in this study were 1) to examine the association between BMI and subsequent hip fracture according to sex and age and 2) to explore whether the importance of known risk factors varied across BMI. We followed 61,787 participants (29,511 female and 32,276 male) in the Cohort of Norway (ages 50-79 years at baseline in 1994-2003) with regard to hip fracture. BMI was calculated from measured height and weight. During a median follow-up period of 8.4 years, 1,603 women and 951 men suffered a hip fracture. Hazard ratios for hip fracture and associated 95% confidence intervals were estimated. After adjustment for potential confounders, women with BMI <22 had a hazard ratio of 1.38 (95% confidence interval (CI): 1.18, 1.60) for hip fracture, as compared with women with BMI 22-24.9; and women with BMI ≥30 had a hazard ratio of 0.57 (95% CI: 0.49, 0.66). Corresponding results in men were hazard ratio = 1.66 (95% CI: 1.35, 2.05) and hazard ratio = 0.77 (95% CI: 0.62, 0.96), respectively. Below age 70 years, there was no further decrease in fracture risk at BMIs of 25 or more, while in women aged 70-79 years, the risk continued to decrease with increasing BMI. The associations between risk factors and hip fracture were similar in strength across BMI strata.

Use of anti-osteoporotic drugs in central Norway after a forearm fracture.

UNLABELLED: Use of anti-osteoporotic drugs (AOD) the first year after a forearm fracture in central Norway was low in the period 2005-2012. Women with fractures used more AOD compared to the general population only in 2006, 2007, and 2011. Female gender, age ≥ 60 years, use of glucocorticosteroids, or ≥ 4 different drugs were associated with AOD use. PURPOSE: The primary aim of this study was to examine time trends in prevalence and incidence of AOD use the first year after a forearm fracture from 2005-2012. Further, secondary aims were to investigate if gender, the number of drugs used before fracture, or use of glucocorticoids influenced the prescription of AOD, and to examine adherence to AOD. METHODS: Data is from the fracture registry in Nord-Trøndelag and the Norwegian Prescription database, including women (N = 1434) and men (N = 513) 40-84 years with their first forearm fracture between 2005 and 2012. AOD were defined as bisphosphonates, teriparatide, denosumab, and raloxifene. Prevalence and incidence were calculated, and prevalent use among women with forearm fracture was compared with the population in Nord-Trøndelag and Norway. Age-adjusted Poisson regression analyses for time trends and odds ratio for treatment with AOD was estimated. Adherence was defined as medication possession ratio ≥ 80 %. RESULTS: The first year after the fracture, 11.2 % of the women and 2.7 % of the men were prevalent users, while 5.1 % and 1.2 %, respectively, were incident users of AOD. Bisphosphonates comprised 98.8 %. AOD use among women with fractures was significantly higher compared to the general population in Nord-Trøndelag only in 2006, 2007, and 2011. There was a trend towards a decline in AOD use among women with fractures from 2005 to 2012 (coefficient -0.05, p = 0.15). Female gender, age ≥ 60 years, use of glucocorticosteroids, or ≥ 4 different drugs the last year before fracture were associated with AOD use. In women, 54.8 % were adherent during 3 years after fracture. CONCLUSIONS: The use of AOD after a forearm fracture was low. An increased focus on osteoporosis in fracture patients is needed for secondary fracture prevention.

Population data on calcium in drinking water and hip fracture: An association may depend on other minerals in water. A NOREPOS study.

BACKGROUND: The Norwegian population has among the highest hip fracture rates in the world. The incidence varies geographically, also within Norway. Calcium in drinking water has been found to be beneficially associated with bone health in some studies, but not in all. In most previous studies, other minerals in water have not been taken into account. Trace minerals, for which drinking water can be an important source and even fulfill the daily nutritional requirement, could act as effect-modifiers in the association between calcium and hip fracture risk. The aim of the present study was to investigate the association between calcium in drinking water and hip fracture, and whether other water minerals modified this association. MATERIALS AND METHODS: A survey of trace metals in 429 waterworks, supplying 64% of the population in Norway, was linked geographically to the home addresses of patients with incident hip fractures (1994-2000). Drinking water mineral concentrations were divided into "low" (below and equal waterworks average) and "high" (above waterworks average). Poisson regression models were fitted, and all incidence rate ratios (IRRs) were adjusted for age, geographic region, urbanization degree, type of water source, and pH of the water. Effect modifications were examined by stratification, and interactions between calcium and magnesium, copper, zinc, iron and manganese were tested both on the multiplicative and the additive scale. Analyses were stratified on gender. RESULTS: Among those supplied from the 429 waterworks (2,110,916 person-years in men and 2,397,217 person-years in women), 5433 men and 13,493 women aged 50-85 years suffered a hip fracture during 1994-2000. Compared to low calcium in drinking water, a high level was associated with a 15% lower hip fracture risk in men (IRR=0.85, 95% CI: 0.78, 0.91) but no significant difference was found in women (IRR=0.98, 95%CI: 0.93-1.02). There was interaction between calcium and copper on hip fracture risk in men (p=0.051); the association between calcium and hip fracture risk was stronger when the copper concentration in water was high (IRR=0.52, 95% CI: 0.35, 0.78) as opposed to when it was low (IRR=0.88, 95% CI: 0.81, 0.94). This pattern persisted also after including potential confounding factors and other minerals in the model. No similar variation in risk was found in women. CONCLUSION: In this large, prospective population study covering two thirds of the Norwegian population and comprising 19,000 hip fractures, we found an inverse association between calcium in drinking water and hip fracture risk in men. The association was stronger when the copper concentration in the water was high.

Educational Inequalities in Post-Hip Fracture Mortality: A NOREPOS Study.

Hip fractures are associated with high excess mortality. Education is an important determinant of health, but little is known about educational inequalities in post-hip fracture mortality. Our objective was to investigate educational inequalities in post-hip fracture mortality and to examine whether comorbidity or family composition could explain any association. We conducted a register-based population study of Norwegians aged 50 years and older from 2002 to 2010. We measured total mortality according to educational attainment in 56,269 hip fracture patients (NORHip) and in the general Norwegian population. Both absolute and relative educational inequalities in mortality in people with and without hip fracture were compared. There was an educational gradient in post-hip fracture mortality in both sexes. Compared with those with primary education only, the age-adjusted relative risk (RR) of mortality in hip fracture patients with tertiary education was 0.82 (95% confidence interval [CI] 0.77-0.87) in men and 0.79 (95% CI 0.75-0.84) in women. Additional adjustments for Charlson comorbidity index, marital status, and number of children did not materially change the estimates. Regardless of educational attainment, the 1-year age-adjusted mortality was three- to fivefold higher in hip fracture patients compared with peers in the general population without fracture. The absolute differences in 1-year mortality according to educational attainment were considerably larger in hip fracture patients than in the population without hip fracture. Absolute educational inequalities in mortality were higher after hip fracture compared with the general population without hip fracture and were not mediated by comorbidity or family composition. Investigation of other possible mediating factors might help to identify new targets for interventions, based on lower educational attainment, to reduce post-hip fracture mortality.

Cohort profile: Norwegian Epidemiologic Osteoporosis Studies (NOREPOS).

AIMS: This paper describes the history, purpose, data collection and contributions in the research collaboration Norwegian Osteoporosis Epidemiologic Studies (NOREPOS). METHODS: NOREPOS encompasses almost 85,000 bone mineral density measurements within Cohort of Norway and data on almost 140,000 hip fractures in Norway 1994-2008. Included are anthropometric measurements, blood pressure, lipids and glucose, and 50 standard questions on sociodemographic factors, diseases and risk factors. Blood samples/DNA are stored. The main research question posed in NOREPOS is why hip fracture rates in Norway are the highest in the world. Data on hip fractures 2009-2013 will be added in 2014. RESULTS: Main findings include: Every hour a Norwegian suffers a hip fracture; hip fracture incidence rates declined after 1999; only 16% of patients used anti-osteoporosis drugs 1 year after hip fracture; 25% of patients died within 1 year after the fracture; 12% suffered a new hip fracture within 10 years; rural dwellers had lower hip and forearm fracture incidence than city dwellers; magnesium in tap water may be protective whereas bacterial contamination, cadmium and lead may be harmful to bone health; low serum vitamin D and E levels were associated with higher hip fracture risk; vitamin A was not associated with fracture risk; and abdominal obesity increased the risk of hip fracture when BMI was accounted for. CONCLUSIONS: NOREPOS encompasses a unique source of information for aetiological research, genetic studies as well as for biomarkers of osteoporosis and fractures. Because of the increasing number of elderly people in Europe, hip fractures will continue to pose an international public health and health care challenge.

Impact of comorbidity, age, and gender on seasonal variation in hip fracture incidence. A NOREPOS study.

UNLABELLED: Based on a total of 136,140 hip fractures, we found a distinct seasonal variation in hip fracture incidence present in subgroups defined by age, gender, and comorbidity. The seasonal variation was most pronounced in the youngest and the healthiest patients. PURPOSE: The purpose of this study was to examine the possible seasonal variation in hip fracture incidence in Norway by comorbidity, age, and gender. METHODS: Data were retrieved from the NOREPOS Hip Fracture Database containing all hip fractures in Norway during the time period 1994-2008. Hip fractures were identified by computerized hospital discharge diagnoses. Charlson comorbidity index was calculated based on additional diagnoses and categorized (0, 1, and ≥2). Summer was defined as June, July, and August and winter as December, January, and February. Incidence rate ratios for hip fracture according to season were calculated by negative binomial models. RESULTS: In patients aged 50-103 years, 136,140 eligible fractures were identified (72.5 % women). The relative risk of hip fracture in winter versus summer was 1.40 (95 % confidence interval (CI) 1.36-1.45) in men and 1.26 (95 % CI 1.23-1.28) in women. June had the lowest number of fractures in both genders. We found seasonal variation in all subgroups by age and gender, although least pronounced in patients >79 years. There was a significant interaction between season and comorbidity (p = 0.022). When comparing winter to summer, we found relative risks of 1.40 (95 % CI 1.31-1.50) in patients with Charlson index = 0, 1.29 (95 % CI 1.19-1.40) in patients with Charlson index = 1, and 1.18 (95 % CI 1.08-1.28) in patients with Charlson index ≥2. CONCLUSIONS: There was a distinct seasonal variation in hip fracture incidence, present in all subgroups of gender, age, or comorbidity. This variation should be accounted for when planning health-care services.

Mortality following the first hip fracture in Norwegian women and men (1999-2008). A NOREPOS study.

Hip fractures are associated with increased mortality and their incidence in Norway is one of the highest worldwide. The aim of this nationwide study was to examine short- and long-term mortality after hip fractures, burden of disease (attributable fraction and potential years of life lost), and time trends in mortality compared to the total Norwegian population. Information on incident hip fractures between 1999 and 2008 in all persons aged 50 years and older was collected from Norwegian hospitals. Death and emigration dates of the hip fracture patients were obtained through 31 December 2010. Standardized mortality ratios (SMRs) were calculated and Poisson regression analyses were used for the estimation of time trends in SMRs. Among the 81,867 patients with a first hip fracture, the 1-year excess mortality was 4.6-fold higher in men, and 2.8-fold higher in women compared to the general population. Although the highest excess mortality was observed during the first two weeks post fracture, the excess risk persisted for twelve years. Mortality rates post hip fracture were higher in men compared to women in all age groups studied. In both genders aged 50 years and older, approximately 5% of the total mortality in the population was related to hip fractures. The largest proportion of the potential life-years lost was in the relatively young-old, i.e. less than 80 years. In men, the 1-year absolute mortality rates post hip fracture declined significantly between 1999 and 2008, by contrast, the mortality in women increased significantly relatively to the population mortality.

Do cadmium, lead, and aluminum in drinking water increase the risk of hip fractures? A NOREPOS study.

The aim of this study was to investigate relations between cadmium, lead, and aluminum in municipality drinking water and the incidence of hip fractures in the Norwegian population. A trace metals survey in 566 waterworks was linked geographically to hip fractures from hospitals throughout the country (1994-2000). In all those supplied from these waterworks, 5,438 men and 13,629 women aged 50-85 years suffered a hip fracture. Poisson regression models were fitted, adjusting for age, region of residence, urbanization, and type of water source as well as other possibly bone-related water quality factors. Effect modification by background variables and interactions between water quality factors were examined (correcting for false discovery rate). Men exposed to a relatively high concentration of cadmium (IRR = 1.10; 95 % CI 1.01, 1.20) had an increased risk of fracture. The association between relatively high lead and hip fracture risk was significant in the oldest age group (66-85 years) for both men (IRR = 1.11; 95 % CI 1.02, 1.21) and women (IRR = 1.10; 95 % CI 1.04, 1.16). Effect modification by degree of urbanization on hip fracture risk in men was also found for all three metals: cadmium, lead, and aluminum. In summary, a relatively high concentration of cadmium, lead, and aluminum measured in drinking water increased the risk of hip fractures, but the associations depended on gender, age, and urbanization degree. This study could help in elucidating the complex effects on bone health by risk factors found in the environment.

Nationwide data on municipal drinking water and hip fracture: could calcium and magnesium be protective? A NOREPOS study.

Norway has a high incidence of hip fractures, and the incidence varies by degree of urbanization. This variation may reflect a difference in underlying environmental factors, perhaps variations in the concentration of calcium and magnesium in municipal drinking water. A trace metal survey (1986-1991) in 556 waterworks (supplying 64% of the Norwegian population) was linked geographically to hip fractures from hospitals throughout the country (1994-2000). In all, 5472 men and 13,604 women aged 50-85years suffered a hip fracture. Poisson regression models were fitted, adjusting for age, urbanization degree, region of residence, type of water source, and pH. The concentrations of calcium and magnesium in drinking water were generally low. An inverse association was found between concentration of magnesium and risk of hip fracture in both genders (IRR men highest vs. lowest tertile=0.80, 95% CI: 0.74, 0.87; IRR women highest vs. lowest tertile=0.90, 95% CI: 0.85, 0.95), but no consistent association between calcium and hip fracture risk was observed. The highest tertile of urbanization degree (city), compared to the lowest (rural), was related to a 23 and 24% increase in hip fracture risk in men and women, respectively. The association between magnesium and hip fracture did not explain the variation in hip fracture risk between city and rural areas. Magnesium in drinking water may have a protective role against hip fractures; however this association should be further investigated.