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Physical activity and overweight are associated with myocardial infarction (MI). However, their joint association with MI remains unclear. Our objective was to examine the independent and joint association between leisure-time physical activity (LTPA), body mass index (BMI) and MI. This prospective cohort study included 16,572 men and women (47.5% women) aged 20-54 years who took part in the second Tromsø Study. At baseline in 1979-80 LTPA was assessed by questionnaire. Data on MI was collected and adjudicated through hospital and causes of death registries between 1979 and 2013. Cox proportional hazards models were used to examine the independent and joint associations between LTPA, BMI and MI. The final sample included 16,104 individuals. During a median follow up of 34 years, 1613 incident cases of MI were recorded. Physical inactivity and elevated BMI were both independently associated with MI (p for trend 0.02 and <0.001). In joint analyses, normal weight, inactive individuals had a 20% higher risk of MI compared to their active counterparts (hazard ratio (HR) 1.20 (1.02-1.41)). The highest risk of MI was seen in obese, inactive individuals when compared to normal weight, active individuals (HR 3.20 (2.30-4.44)). The risk of MI increased with increasing BMI regardless of the activity level. HRs were lower for active compared to inactive individuals within the same BMI category. The findings suggest that LTPA and BMI are independently associated with risk of MI. LTPA seems to attenuate but not eliminate the risk of MI associated with excess bodyweight., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Positive association between body weight and bone mass is well established, and the concept of body mass index (BMI) is associated with higher areal bone mineral density (aBMD) and reduced fracture risk. BMI, that comprises both fat mass (FM) and lean mass (LM) may contribute to peak bone mass achievement in different ways. This study explored the influence of body composition in terms of total body LM and FM on hip aBMD-values in adolescence., Methods: In 2010/2011, 93% of the region's first-year upper-secondary school students (15-17 years old) in Tromsø, Norway attended the Tromsø Study, Fit Futures. Areal BMD at femoral neck (aBMD FN ) and total hip (aBMD TH ) (g/cm 2 ), total body LM and FM (g) were measured by dual energy X-ray absorptiometry (DXA). Height and weight were measured, and BMI calculated. Lifestyle variables were collected by self-administered questionnaires and interviews, including questions on time spent on leisure time physical activity. Stratified analyses of covariance and regression models included 395 girls and 363 boys. Crude results were adjusted for age, height, sexual maturation, physical activity levels, vitamin D levels, calcium intake, alcohol consumption and smoking habits., Results: Unadjusted distribution indicated higher aBMD-levels at higher LM-levels in both genders (p < 0.001), but higher aBMD at higher FM-levels were found only in girls (p < 0.018). After multiple adjustments, aBMD FN -levels in girls were associated by 0.053 g/cm 2 and 0.032 g/cm 2 per standard deviation (SD) change in LM and FM (p < 0.001). Corresponding values in boys were 0.072 and 0.025 (p < 0.001). The high LM groups accounted for the highest aBMD-levels, while aBMD-levels at the LM/FM-combinations indicated different patterns in girls compared to boys. The adjusted odds ratio (95% CI) for low levels of aBMD FN was 6.6 (3.4,13.0) in boys, compared to 2.8 (1.6,4.9) in girls per SD lower LM., Conclusions: LM and FM should be regarded as strong predictors for bone mass and hence bone strength in adolescents. A gender specific difference indicated that high lean mass is of crucial importance prominently in boys. In adolescents with low lean mass, especially in girls, high fat mass may partially ameliorate the effect of deficient lean mass levels.

Background: The aim was to describe secular trends in leisure time physical activity (LTPA) and work related physical activity (WPA) from 1979 to 2008. Additionally, we explored potential cross-sectional and longitudinal correlates of LTPA and WPA., Methods: Data are collected from 34,898 individuals (49.7% men) aged >20 years who participated in at least one Tromsø Study survey between 1979 and 2008. In each survey, the participants completed a self-administered questionnaire and underwent physical examinations. LTPA and WPA were assessed by the validated "Saltin-Grimby" 4-scale questions. Potential correlates of LTPA and WPA (sex, age, body mass index (BMI), education, smoking, self-reported cardiovascular disease, self-perceived health, and employment status) were tested using ordinal logistic regression., Results: The age-adjusted prevalence of participants being inactive in leisure time remained relatively stable around 20% from 1979 to 2008 (range 19.9-23.6%). The age-adjusted prevalence of moderate-vigorous LTPA decreased from 23.2% in 1979-80 to 16.0% in 2001, thereafter the prevalence increased to 24.3% in 2007-08 (P <0.05). The age-adjusted prevalence of being mostly sedentary at work increased gradually from 35.5% in 1979-80 to 53.4% in 2007-08 (P <0.05). Sex, age, education, and smoking were identified as cross-sectional correlates of LTPA and WPA (P <0.05). Men had higher odds of engaging in LTPA than women (adjusted OR 1.52 [95% CI 1.39-1.67] in 2007-08), whereas the association between sex and WPA shifted over time. High education level, not being a smoker, and high WPA were associated with high LTPA, whereas low education level, being a smoker, and high levels of LTPA were associated with high WPA (P <0.05). In general, odds of engaging in LTPA and WPA decreased with age (P <0.05). Individuals with healthy BMI had higher odds of being in a higher LTPA level than those who were underweight and obese (P <0.05). Longitudinal analyses identified sex, age, education, smoking, WPA, and LTPA measured in 1979-80 as determinants of LTPA in 2007-08., Conclusions: In Norwegian adults, the proportion of sedentary WPA increased from 1979 to 2008, whereas the proportion of inactive LTPA remained stable. Being female, older, smoker, obese or underweight, and low education level were associated with low LTPA levels.

Aims: The objective was to examine the association of physical activity and resting heart rate (RHR) with hospital-diagnosed atrial fibrillation (AF) in a Norwegian cohort., Methods and Results: This prospective study included 20 484 adults (50.3% men) who participated in the third Tromsø Study survey in 1986-87. At baseline, physical activity was assessed by a validated questionnaire, and RHR was objectively measured. Participants were followed from baseline through 2010 with respect to incident cases of hospital-diagnosed AF documented on an electrocardiogram. During a mean follow-up period of 20 years (409 045 person-years), 750 participants (70.5% men) were diagnosed with AF. Compared with the low physical activity group, moderately active individuals had a 19% lower risk of any AF [adjusted hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.68-0.97], whereas highly active had similar risk of AF. Vigorously active individuals showed a non-significantly higher risk of AF (adjusted HR 1.37, 95% CI 0.77-2.43). Risk of AF increased with decreasing RHR (adjusted HR 0.92, 95% CI 0.86-0.98 for each 10 b.p.m. increase in RHR), and RHR < 50 b.p.m. was a risk factor for AF (P < 0.05)., Conclusion: In this prospective cohort study, leisure time physical activity was associated with AF in a J-shaped pattern. Moderate physical activity was associated with a reduced risk of AF, whereas higher activity levels attenuated the benefits of moderate activity. Low RHR was a risk factor for AF. Our results support the hypothesis that moderate and vigorous physical activity may affect AF risk via different pathophysiological mechanisms., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

Our aim was to examine associations between leisure time physical activity and risk of non-vertebral fractures in men and women aged ≥55 years, with focus on the anatomical fracture location. Self-reported physical activity was registered in 3,450 men and 4,072 women aged 55-97 years at baseline in the Tromsø Study, Norway, in 1994-1995. Non-vertebral fractures were registered through December 31, 2009. During 75,546 person-years at risk, 1,693 non-vertebral fractures were identified. Risk of any non-vertebral fracture decreased with increasing physical activity level in men (P (trend) = 0.006) and non-significantly in women (P (trend) = 0.15), after adjustment for age, body mass index, height, smoking, and previous fracture. The reduced fracture risk was due to a reduced risk in the weight-bearing skeleton, particular at the hip, whereas risk of fracture in the non-weight-bearing skeleton was not related to physical activity. At weight-bearing sites, an inverse relationship between physical activity and fracture risk was present in both sexes (P (trend) ≤ 0.013). Compared with sedentary subjects, the most active men and women had respectively 37% (HR = 0.63, 95% CI: 0.45, 0.88) and 23% (HR = 0.77, 95% CI: 0.62, 0.95) reduced fracture risk in the weight-bearing skeleton. Physical activity is associated with reduced fracture risk at weight-bearing sites, with no associations at non-weight-bearing sites, in both sexes. Habitual physical activity is an important amendable approach to prevent hip fracture.

Although the positive association between physical activity and bone mineral density (BMD) is well established, few epidemiological studies have investigated the long-term associations between physical activity during adulthood and BMD later in life. The aim of this prospective, population-based study was to examine the association between leisure time physical activity in adulthood and areal BMD (aBMD) later in life. We examined 1,766 women and 1,451 men aged 20-54 years at baseline who were followed up 22 years later, as part of a population-based study in Norway. Leisure time physical activity was assessed by questionnaire at baseline and follow-up. aBMD was measured at the hip and forearm at follow-up, using X-ray absorptiometry. The association between aBMD and physical activity was analyzed using general linear models. We observed a positive linear trend in aBMD across physical activity levels in both women and men, after adjustments for baseline age, height, weight, and smoking status (P < 0.05). The relationship between aBMD and leisure time physical activity was consistent over different sites of the hip (total hip, femoral neck and trochanter area) and forearm (distal and ultradistal area). In a subsample of 2,436 men and women under 70 years of age, those who where sedentary at both baseline and follow-up (6%) had lower aBMD than those who were moderately active or active at both baseline and follow-up (71%) (P

Background: A more sedentary way of life and less physical activity has increased the risk of many common health problems. This implicates a need for knowledge about activity patterns and determinants for physical activity in Norway., Material and Method: 2914/6836 (43 %), 1499 women and 1415 men (18 - 69 years), responded to a questionnaire survey performed in the county of Nordland in 2002. The total physical activity was estimated from the question "How active are you?" for 22 different leisure time activities. Activity was expressed in number of Metabolic Equivalent hours per week (METh/week) and as the sum of METh/week. Leisure-time activity was related to age, sex, health and level of education of the respondents., Result and Interpretation: Backcountry hiking and outdoor life comprise a large part of the physical activities undertaken by adults in Nordland. Women are slightly less physically active than men. The median METh/week was 21.7 for women and 24.7 for men. Physical activity decreases slightly with age for both women and men. The correlation between self-rated health and physical activity is positive, and dependence of the level of education shows an overall positive trend. The results from this survey emphasize the need for standardized Norwegian questionnaires about physical activity and an agreed method of measuring physical activity.

Background: Evidence pertaining to whether more recent born generations of adults reaching old age have better physical capability than previous generations is scarce and inconclusive. We aimed to investigate birth cohort differences in grip strength.Methods: The study comprised 5,595 individuals from the Tromsø study waves in 1994/1995, 2007/2008, and 2015/2016. Grip strength (bar) was measured using a Martin vigorimeter, and compared across three birth cohorts of 66- to 84-year-olds (born in: 1910-1929, 1923-1942, 1931-1949), as well as within narrower age bands to ensure nonoverlapping cohorts. Linear regression was applied, adjusted for age, education, smoking, physical activity, height, and weight.Results: Grip strength increased across birth cohorts, and the increase was similar within narrower age bands and across genders. Overall, the increase in sex-adjusted mean grip strength when comparing the first and latest born cohorts, born 21 years apart, was 0.06 bar (95% CI 0.04, 0.07). Higher educational levels, and greater height and weight in the most recent born cohort explained 48% of this difference, while reduced smoking and physical inactivity in more recent born cohorts had little impact.Conclusions: Our findings suggest higher grip strength in more recent birth cohorts of older Norwegian adults, which can be partly attributed to higher education and greater height. This difference corresponded to a 5-year difference in grip strength; more recent born generations of 80-year-olds, therefore, have similar mean grip strength as 75-year-olds born one generation earlier. [ABSTRACT FROM AUTHOR]

The article presents a study on tracking the physical activity in adults in leisure time during the last three decades in northern Norway. This population-based study was conducted on 5432 men and women who attended the Tromso Study that was performed in 1979-1980 and estimated the tracked physical activity using the Spearman correlation coefficient and weighted statistics. It shows substantial physical activity during early adulthood and it's indication of an active lifestyle in later part of life.