Contribution of elevation and residential proximity to the coast in explaining geographic variations in hip fracture incidence. A Norwegian Epidemiologic Osteoporosis Studies (NOREPOS) study.

A higher risk of hip fracture was found in areas of Norway at higher elevation and farther from the coast. However, the previously seen county variations could not be explained by these geographical factors. INTRODUCTION: Norway is an elongated country extending north of the Arctic Circle with substantial coast-inland variation in topography and climate. Differences in hip fracture incidence between counties and a distinct seasonal variation have previously been shown. The aim of the current study was to explore these variations further by considering associations of height above sea level (elevation) and distance to the coast with hip fracture incidence. METHODS: All patients with hip fractures admitted to Norwegian hospitals in the period 2009-2018 were included. Individual residential elevation and distance to the coast was calculated in Geographic Information Systems and combined with individual-level population data on all Norwegians 50 years of age or older during the observation period, including hospital information on fractures. Age-standardized incidences rate and incidence rate ratios with 95% confidence intervals (IRR, 95% CI) according to elevation and coastal proximity were estimated. The associations were tested using Poisson models adjusting for sex, urban/rural location of residency, country of birth, and season of hip fracture occurrence. RESULTS: From 2009 to 2018, there were 85,776 first hip fractures. There was an increasing risk with higher residential elevation (above versus below mean) for women: IRR = 1.04, 95% CI: 1.02, 1.05), but not for men (IRR = 1.00, 95% CI: 0.97, 1.02). Incidence of hip fracture increased with distance from the coast. Women residing the farthest away from the coast (above versus below mean distance) had a higher age-adjusted incidence of hip fracture compared to those living closer to the coast (IRR = 1.04 (95% CI: 1.02, 1.06), whereas no association was found in men (IRR = 1.00 (95% CI: 1.00, 1.01). Combining elevation and distance to coast showed a higher incidence in women living at high elevation far from the coast compared with women living at low elevation near the coast (IRR = 1.07, 95% CI: 1.04, 1.10). A similar result was found in men but only for hip fractures occurring during March-May (IRR = 1.07, 95% CI: 1.00, 1.15). The previously shown patterns of county differences and seasonal variations were unchanged when considering geography. CONCLUSION: We found a somewhat higher incidence of hip fracture in inland residents living in areas of high elevation, as compared to those living in more coastal proximity; however, the geographic variation did not explain county and seasonal differences in fracture incidence in Norway. More in-depth analyses on temperature and climate factors may give further clues.

Ethnic differences in risk of hip fracture in Norway: a NOREPOS study.

Hip fracture is a major public health problem, and the incidence rates vary considerably between countries. Ethnic differences in bone mineral density have been identified as a factor to explain some of the geographical differences in rates of hip fracture. In this Norwegian register-based study, we found that all immigrant groups experienced lower risk of hip fracture than individuals born in Norway. INTRODUCTION: Norway is among the countries with the highest incidence rates. The aim of this study was to investigate differences in risk of hip fracture between ethnic groups living in Norway. METHODS: We linked individuals in the Norwegian Population and Housing Census conducted in 2001 and a database consisting of all hip fractures in Norway in the period 2001-2013. Residents (n = 1,392,949) between 50 and 89 years and born in nine different geographical regions of the world were examined, and we computed age-standardized incidence rates for the different geographic regions-denoted ethnic groups in the paper. Gender-stratified Cox regression analysis, adjusted for age, was used to model risk of hip fracture as a function of region of birth. RESULTS: Age-standardized incidence rates of hip fracture varied considerably between regions of birth living in Norway, in both genders. All immigrant groups had lower risk of hip fracture compared to the Norwegian-born population. Immigrants from Central and Southeast Asia had the lowest risk of hip fracture when compared to individuals born in Norway (HR = 0.2, 95% CI 0.1-0.3 and HR =0.2, 95% CI 0.2-0.4 in men and women, respectively). CONCLUSION: Lower risk of hip fracture was found in all immigrant groups compared to the Norwegian-born majority population.

Geographic variations in hip fracture incidence in a high-risk country stretching into the Arctic: a NOREPOS study.

There are geographic variations in hip fracture incidence rates across Norway, with a lower incidence in the coastal areas of the southwest and in the Arctic north, contrary to what may be expected with regard to vitamin D exposure from sunlight. The regional differences have become smaller in recent years. INTRODUCTION: To investigate geographic variation in hip fracture incidence within Norway and regional differences in time trends. METHODS: All hip fractures treated in Norwegian hospitals 2002-2013 were included, and demographic information was obtained from Statistics Norway. Age-standardized incidence rates were calculated separately for 19 counties. Incidence rate ratios with 95% confidence intervals for county differences and time trends were estimated using Poisson regression. RESULTS: Age-standardized number of hip fractures per 10,000 person-years varied between counties from 69 to 84 in women and from 34 to 41 in men. The highest rates were observed in the southeastern capital city of Oslo, while rates were low in the four northernmost counties. There was an east-west gradient, with lower incidence in the coastal southwest compared with the southeast. Women showed a statistically significant decline during 2002-2013 in almost all counties (up to 31%). In men, only a few counties showed a decline. In both genders, hip fracture rates at age 80 in the combined five counties with the highest rates were significantly higher than in the combined five counties with the lowest rates across the period, although the trends converged over time. CONCLUSIONS: In Norway, the hip fracture incidence was lower in the north compared with the south. In addition, we observed an east-west gradient with the highest incidence in the southeast and lower incidence in the coastal southwest. While there has been an overall declining trend in hip fracture incidence over time, regional differences are still apparent.

The association between alcohol consumption and risk of hip fracture differs by age and gender in Cohort of Norway: a NOREPOS study.

The association between alcohol consumption and hip fracture differed by gender: Men aged 30-59 years drinking frequently or 14+ gl/week had higher risk than moderate drinkers. No significant association was seen in older men. Women not drinking alcohol had higher risk than those drinking moderately both regarding frequency and amount. INTRODUCTION: We aimed to examine alcohol consumption and risk of hip fracture according to age and gender in the population-based Cohort of Norway (1994-2003). METHODS: Socio-demographics, lifestyle, and health were self-reported and weight and height were measured in 70,568 men and 71,357 women ≥ 30 years. Information on subsequent hip fractures was retrieved from hospitals' electronic patient registries during 1994-2013. Frequency of alcohol consumption was categorized: never/seldom, moderate (≤ 2-3 times/week), or frequent (≥ 4 times/week), and amount as number of glasses per week: 0, 1-6, 7-13, 14-27, and 28+. Type of alcohol (wine vs. beer/hard liquor) was also examined. Cox's proportional hazards regression was used to estimate hazard ratios (HRs) stratified on gender and baseline age < 60 and ≥ 60 years. RESULTS: During median 15-year follow-up, 1558 men and 2511 women suffered a hip fracture. Using moderate drinkers as reference, men < 60 years drinking frequently had multivariable adjusted HR = 1.73 (CI 1.02-2.96) for hip fracture and more than 2.5 times higher risk if they consumed 14+ glasses compared to 1-6 glasses per week. In other groups of age and gender, no statistically significant increased risk was found in those consuming the highest levels of alcohol. Compared to women with moderate or frequent alcohol use, never/seldom-drinking women had the highest fracture risk. In women, use of wine was associated with lower fracture risk than other types of alcohol. CONCLUSIONS: Risk of hip fracture was highest in men < 60 years with the highest frequency and amount of alcohol consumption and in non-drinking women.

Excess mortality following hip fracture: impact of self-perceived health, smoking, and body mass index. A NOREPOS study.

Self-perceived health, smoking, and body mass index measured years before the hip fracture predicted excess post-hip fracture mortality, and even hip fracture patients with the most favorable levels of these risk factors had higher mortality than subjects who did not fracture. INTRODUCTION: This study aimed to investigate the impact of pre-fracture self-perceived health, smoking, and body mass index (BMI) on excess post-hip fracture mortality using matched peers without hip fracture as reference. METHODS: The study was based on the Cohort of Norway (CONOR) consisting of 10 regional health studies (1994-2003) and the NOREPOS hip fracture database (1994-2008). A matched cohort design was used to compare survival between hip fracture patients and subjects without fracture (matched on gender, age at participation in CONOR, and study site). Subjects aged ≥60 years were included. Hazard ratios were estimated using stratified Cox regression. Age-standardized mortality was also calculated. RESULTS: Overall, hip fracture patients (N = 3177) had a 2.26-fold (95 % CI 2.13, 2.40) increased mortality compared to matched subjects (N = 20,282). The highest excess mortality was found in hip fracture patients reporting poor health (HR 4.08, 95 % CI 3.17, 5.26) and daily smoking (HR 3.25, 95 % CI 2.89, 3.66) and in patients with BMI <18.5 (HR 3.07, 95 % CI 2.11, 4.47) prior to the fracture. However, excess mortality was also observed in hip fracture patients in all other categories of BMI, self-perceived health, and smoking. CONCLUSIONS: Information on self-perceived health, smoking, and BMI collected years before hip fracture predicted excess post-hip fracture mortality, and even hip fracture patients with the most favorable levels of these risk factors had higher mortality than the matched subjects who did not fracture. This suggests that both pre-fracture health status and factors related to the hip fracture itself might affect post-hip fracture mortality.

Continued decline in hip fracture incidence in Norway: a NOREPOS study.

UNLABELLED: The previously reported decline in age-adjusted hip fracture rates in Norway during 1999-2008 continued after 2008. The annual number of hip fractures decreased in women and increased in men. INTRODUCTION: Norway has among the highest hip fracture incidence rates ever reported despite previously observed declining rates from 1999 through 2008. The aim of the present study was to investigate whether this downward trend continued through 2013, and to compare gender-specific trends in 5 year age-groups during three time periods: 1999-2003, 2004-2008, and 2009-2013. METHODS: All hip fractures (cervical, trochanteric, and sub-trochanteric) admitted to Norwegian hospitals were retrieved. Annual age-standardized incidence rates of hip fracture per 10,000 person-years by gender were calculated for the period 1999-2013. Time trends were tested by age-adjusted Poisson regression. RESULTS: From 1999 through 2013 there were 140,136 hip fractures in persons aged 50 years and above. Age-adjusted hip fracture incidence rates declined by 20.4 % (95 % CI: 18.6-20.1) in women and 10.8 % (95 % CI: 7.8-13.8) in men, corresponding to an average annual age-adjusted decline of 1.5 % in women and 0.8 % in men. Except for the oldest men, hip fracture rates declined in all age-groups 70 years and older. The average annual number of fractures decreased in women (-0.3 %) and increased in men (+1.1 %). CONCLUSIONS: During the past 15 years, hip fracture rates have declined in Norway. The forecasted growing number of older individuals might, however, cause an increase in the absolute number of fractures, with a substantial societal economic and public health burden.

Self-perceived memory loss is associated with an increased risk of hip fracture in the elderly: a population-based NOREPOS cohort study.

BACKGROUND: An early detection of memory loss may hold great value as a predictor for dementia. Dementia has already been associated with higher risk of hip fracture. Our aim was to examine the prospective association between self-reported memory-loss and the risk of subsequent hip fracture in the elderly. METHODS: A population-based prospective cohort study design was used. Information on four self-perceived memory loss questions was obtained from questionnaires in 3 health surveys performed in Norway during the years 2000-2001. A total of 7154 men and 2462 women aged 67-77 years old were followed for a median of 7.8 years. Hip fracture information (n = 287 in men, and n = 237 in women) was obtained from NORHip (a database including all hip fractures treated in Norway from year 1994). Cox survival analysis was performed to estimate HR (hazard ratio). RESULTS: The risk of sustaining a hip fracture were higher in those who reported to forget things they had just heard or read, with a HR of 1.52 (1.19--1.95) in men and HR 1.60 (1.23--2.07) in women after adjustment for relevant confounders. Women reporting to forget where they had put things also had higher risk of later hip fracture with a HR of 1.58 (1.20--2.07). Answering yes in both questions showed stronger association with sustaining a first hip fracture compared with those who gave a negative response in both questions, with a multivariate adjusted HR of 1.41 (IC 95 % 1.06--1.88) in men and 1.90 (IC 95 % 1.39--2.60) in women. The two last questions did not show a significant association with hip fracture. CONCLUSIONS: There was a higher risk of hip fracture in elderly who reported self-perceived memory loss. Due to the serious implications of sustaining a hip fracture, early detection of risk groups is important for preventive interventions.

Abdominal obesity increases the risk of hip fracture. A population-based study of 43,000 women and men aged 60-79 years followed for 8 years. Cohort of Norway.

BACKGROUND: The question as to whether abdominal obesity has an adverse effect on hip fracture remains unanswered. The purpose of this study was to investigate the associations of waist circumference, hip circumference, waist-hip ratio, and body mass index with incident hip fracture. METHODS: The data in this prospective study is based on Cohort of Norway, a population-based cohort established during 1994-2003. Altogether 19,918 women and 23,061 men aged 60-79 years were followed for a median of 8.1 years. Height, weight, waist and hip circumference were measured at baseline using standard procedures. Information on covariates was collected by questionnaires. Hip fractures (n = 1,498 in women, n = 889 in men) were identified from electronic discharge registers from all general hospitals in Norway between 1994 and 2008. RESULTS: The risk of hip fracture decreased with increasing body mass index, plateauing in obese men. However, higher waist circumference and higher waist-hip ratio were associated with an increased risk of hip fracture after adjustment for body mass index and other potential confounders. Women in the highest tertile of waist circumference had an 86% (95% CI: 51-129%) higher risk of hip fracture compared to the lowest, with a corresponding increased risk in men of 100% (95% CI 53-161%). Lower body mass index combined with abdominal obesity increased the risk of hip fracture considerably, particularly in men. CONCLUSION: Abdominal obesity was associated with an increased risk of hip fracture when body mass index was taken into account. In view of the increasing prevalence of obesity and the number of older people suffering osteoporotic fractures in Western societies, our findings have important clinical and public health implications.

Forecasting the burden of future postmenopausal hip fractures.

SUMMARY: A growing elderly population is expected worldwide, and the rate of hip fractures is decisive for the future fracture burden. Significant declines in hip fracture rates in Norway, the USA, France, Germany, and the UK are required to counteract the impact of the ageing effects. INTRODUCTION: This study aims to evaluate the consequences of the expected growth of the elderly population worldwide on the hip fracture burden using Norway as an example. Furthermore, we wanted to estimate the decline in hip fracture rates required to counteract the anticipated increase in the burden of hip fracture for Norway, the USA, France, Germany, and the UK. METHODS: The burden of future postmenopausal hip fractures in Norway were estimated given (1) constant age-specific rates, (2) continued decline, and (3) different cohort scenarios. Based on population projection estimates and population age-specific hip fracture rates in women 65 years and older, we calculated the required declines in hip fracture rates needed to counteract the growing elderly populations in Norway, the USA, France, Germany, and the UK. RESULTS: The level of age-specific hip fracture rates had a huge impact on the future hip fracture burden in Norway. Even if the hip fracture rates decline at the same speed, a 22 % increase in the burden of hip fractures can be expected by 2040. An annual decline in hip fracture rates of 1.1-2.2 % until 2040 is required to counteract the effects of the growing elderly population on the future burden of hip fractures in Norway, the USA, France, Germany, and the UK. CONCLUSIONS: Hip fracture rates have a great impact on the burden of hip fractures. The rates will have to decline significantly to counteract the impact of a growing elderly population. A change in preventive strategies and further studies are warranted to identify the complex causes associated to hip fractures.

Weight loss and distal forearm fractures in postmenopausal women: the Nord-Trøndelag health study, Norway.

SUMMARY: Weight loss is a risk factor for hip fractures, but few studies have evaluated the effect of weight loss on distal forearm fracture risk. In this longitudinal study including 7,871 postmenopausal women, weight loss of 5% or more was associated with an increased risk of distal forearm fractures. INTRODUCTION: Weight loss is an established risk factor for hip fractures, but little is known about weight loss and distal forearm fractures risk. METHODS: The study included 7,871 women aged 65 years or more in the Nord-Trøndelag health study (HUNT) in 1994-1995 (HUNT II) who also had their height and weight measured in 1984-1986 (HUNT I). Forearm bone mineral density (BMD) by single energy x-ray absorptiometry was available for 5,688 women (HUNT II). Fractures sustained after HUNT II were registered during an average of 5.8 years. RESULTS: A total of 536 women sustained a distal forearm fracture. After adjustments for age and body mass index (BMI) at HUNT I, women who lost > or =5% of their weight between HUNT I and HUNT II had a relative risk of fractures of 1.33 (95% confidence interval: 1.09, 1.62) compared with the rest of the women. The higher risk of forearm fracture among women with weight loss was at least partially explained by their lower forearm BMD. CONCLUSION: Weight loss of 5% or more was associated with a 33% increased risk of distal forearm fractures.

Regional differences in hip bone mineral density levels in Norway: the NOREPOS study.

SUMMARY: Large regional differences in hip fracture rates within Norway have previously been shown. However, regional differences in hip bone mineral density (BMD) have not yet been assessed. In this study including 10,504 hip scans, there were significant regional differences in BMD. Further studies to address reasons for the regional differences in hip fracture risk are warranted. INTRODUCTION: Bone mineral density (BMD) at the hip is an important determinant of hip fracture. While regional differences in Norwegian hip fracture rates have previously been shown, no comparative studies of hip BMD have been conducted. METHODS: Total hip BMD was measured by DXA in two population-based studies across Norway during 1997-2002. Valid hip scans with in vivo calibration were obtained from 5127 subjects in Tromsø (age 30-89 years) and 5377 subjects in Bergen (age 47-50 and 71-75 years). RESULTS: Women >or=60 years in Tromsø had 0.052 g/cm(2) higher age-adjusted BMD than women in Bergen, whereas BMD among women <60 years was similar in Tromsø and Bergen. Age-adjusted total hip BMD was 0.035 g/cm(2) lower in men >or=60 years in Bergen compared with Tromsø, and the corresponding figure for men <60 years was 0.028 g/cm(2). While adjustment for body mass index explained some, but not all of the differences, smoking, physical activity, diabetes prevalence, self-perceived health, intake of alcohol and estrogen use did not. CONCLUSIONS: Regional differences in BMD at the hip were found in Norway. Reasons for this and potential impact on hip fracture rates should be explored in further studies.