Tone Kristin Omsland

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.

Lifestyle Impact on Lifetime Bone Loss in Women and Men The Tromsø Study

A physically active, nonsmoking lifestyle with weight maintenance positively influences bone health. The authors estimated the effect of lifestyles on peak bone mass and lifetime bone loss in the Tromsø Study, Norway. Bone mineral density (BMD) was measured at distal and ultradistal forearm sites with single x-ray absorptiometric devices in 7,948 men and women aged 24-84 years in 1994-1995 and repeated in 2001 in 6,182 subjects. BMD was significantly higher at peak than at old age. However, the difference, estimated as lifetime loss, varied between lifestyle groups. Lifetime loss in nonsmoking, physically active men with a body mass index of 25 kg/m(2) compared with smoking, inactive, and lean men was 15.9% and 25.9% at the distal site and 17.5% and 29.7% at the ultradistal site, respectively. In women, the corresponding loss estimates were 34.4% and 45.7% and 35.6% and 55.7%, respectively. The differences in BMD at the age of 80 years correspond to an increased forearm fracture risk of 69% in men and 85% in women with greatest bone loss. A lifestyle including nonsmoking, a high physical activity level, and a high body weight reduces bone loss and fracture risk in both sexes, with increasing effect from peak bone mass to old age.

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

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.

Progressively Increasing Fracture Risk With Advancing Age After Initial Incident Fragility Fracture: The Tromso Study

The risk of subsequent fracture is increased after initial fractures; however, proper understanding of its magnitude is lacking. This population‐based study examines the subsequent fracture risk in women and men by age and type of initial incident fracture. All incident nonvertebral fractures between 1994 and 2009 were registered in 27,158 participants in the Tromsø Study, Norway. The analysis included 3108 subjects with an initial incident fracture after the age of 49 years. Subsequent fracture (n = 664) risk was expressed as rate ratios (RR) and absolute proportions irrespective of death. The rates of both initial and subsequent fractures increased with age, the latter with the steepest curve. Compared with initial incident fracture rate of 30.8 per 1000 in women and 12.9 per 1000 in men, the overall age‐adjusted RR of subsequent fracture was 1.3 (95% CI, 1.2–1.5) in women, and 2.0 (95% CI, 1.6–2.4) in men. Although the RRs decreased with age, the absolute proportions of those with initial fracture who suffered a subsequent fracture increased with age; from 9% to 30% in women and from 10% to 26% in men, between the age groups 50–59 to 80+ years. The type of subsequent fracture varied by age from mostly minor fractures in the youngest to hip or other major fractures in the oldest age groups, irrespective of type and severity of initial fracture. In women and men, 45% and 38% of the subsequent hip or other major fractures, respectively, were preceded by initial minor fractures. The risk of subsequent fracture is high in all age groups. At older age, severe subsequent fracture types follow both clinically severe and minor initial incident fractures. Any fragility fracture in the elderly reflects the need for specific osteoporosis management to reduce further fracture risk.

More forearm fractures among urban than rural women: The NOREPOS study based on the Tromsø study and the HUNT study†

Higher rates of hip fracture and all fractures combined have been observed in urban compared with rural areas, but whether there are urban‐rural differences in distal forearm fracture rates is less studied. The aim of this longitudinal study was to compare the incidence of forearm fracture in postmenopausal women in urban and rural areas in Norway and to investigate risk factors that could explain potential fracture differences. The study included data from 11,209 women aged 65 years or more who participated in two large health studies, the Tromsø Health Study in 1994–1995 and the Nord‐Trøndelag Health Study in 1995–1997. Forearm bone mineral density (BMD) was measured by single‐energy X‐ray absorptiometry in a subsample of women (n = 7333) at baseline. All women were followed with respect to hospital‐verified forearm fractures (median follow‐up 6.3 years). A total of 9249 and 1960 women lived in areas classified as rural and urban, respectively. Urban women had an increased forearm fracture risk [relative risk (RR) = 1.29, 95% confidence interval (CI) 1.09–1.52] compared with women in rural areas. Rural women had higher body mass index (BMI) than urban women, and the RR was moderately reduced to 1.21 (95% CI 1.02–1.43) after BMI adjustments. Rural women had the highest BMD. In the subgroup with measured BMD, adjustments for BMD changed the urban versus rural RR from 1.21 (95% CI 0.96–1.52) to 1.05 (95% CI 0.83–1.32), suggesting that BMD is an important explanatory factor. In conclusion, higher rates of forearm fractures was found in urban compared with rural women.

Ten-year risk of second hip fracture. A NOREPOS study

BACKGROUND Second hip fracture risk is elevated after the first, however whether risk differs with age, by sex or over time is not well known. OBJECTIVE To examine the risk of second hip fracture by sex, age and time after first hip fracture. DESIGN Data on all hip fractures in subjects 50 years and older and treated in Norwegian hospitals during 1999-2008 were retrieved. Surgical procedure codes and additional diagnosis codes were used to define incident fractures. Survival analyses with and without adjustment for competing risk of death were used to estimate the risk of second hip fracture. RESULTS Among the 81,867 persons who sustained a first hip fracture, 6161 women and 1782 men suffered a second hip fracture during follow-up. The overall age-adjusted hazard ratio (HR) of a second hip fracture did not differ between the sexes (women versus men, HR=1.03; 95% confidence interval (CI): 0.98-1.09). Taking competing risk of death into account, the corresponding age-adjusted HR of a second hip fracture was 1.40 (95% CI: 1.33-1.47) in women compared to men. The greater risk in women was due to a higher mortality in men. Based on competing risk analyses, we estimate that 15% of women and 11% of men will have suffered a second hip fracture within 10 years after the first hip fracture. The ten-year cumulative incidence was above 10% in all age-groups, except in men 90 years and older. CONCLUSION Fracture preventive strategies have a large potential in both women and men who suffer their first hip fracture due to the high risk of another hip fracture.

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.

Educational Inequalities in Post‐Hip Fracture Mortality: A NOREPOS Studys

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.

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

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.

Homocysteine-Lowering Treatment and the Risk of Fracture: Secondary Analysis of a Randomized Controlled Trial and an Updated Meta-Analysis: HOMOCYSTEINE-LOWERING TREATMENT AND THE RISK OF FRACTURE

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.