Showing papers by "Maja-Lisa Løchen published in 2015"

Association between diastolic dysfunction and future atrial fibrillation in the Tromsø Study from 1994 to 2010

Abstract: Published version. Source at http://doi.org/10.1136/heartjnl-2015-307438 . License in accordance with the journal's policy - CC BY-NC 4.0 .

Longitudinal and Secular Trends in Blood Pressure Among Women and Men in Birth Cohorts Born Between 1905 and 1977: The Tromsø Study 1979 to 2008.

Abstract: High blood pressure is a modifiable risk factor for cardiovascular disease. Previous studies showing a blood pressure decline in recent decades lack data to follow individuals born in different decades from early and middle adulthood to older age. We investigated changes in age-specific blood pressure by repeated measurements in 37 973 women and men born 1905 to 1977 (aged 20–89 years) examined ≤5× between 1979 and 2008 in the population-based Tromso Study. Mixed models were used to estimate time trends. Mean systolic and diastolic blood pressure decreased from 1979 to 2008 in both genders in the age groups 30 to 89 years. The decrease was similar in the 80th percentile and the 20th percentile of the population blood pressure distribution. The decrease in systolic blood pressure in age group 40 to 49 years was 10.6 mm Hg in women and 4.5 mm Hg in men. Systolic blood pressure increased with age in women and men born 1920 to 1949, whereas a decrease or flattening of curve was observed in the younger birth cohorts. Thus, we found both time periodic and cohort effects, and trends were more pronounced in women than in men. The findings suggest changes in blood pressure in the population rather than an effect of treatment of high-risk individuals.

The validity of self-reported information about hypertensive disorders of pregnancy in a population-based survey: the Tromsø Study.

Abstract: Objective To investigate the validity of self-reported information about hypertensive disorders in previous pregnancies among women participating in the fourth survey of the Tromso Study. Design Retrospective cohort study with case–control design. Population Parous women participating in the fourth survey of the Tromso Study. Methods Medical records including partograms of 200 randomly selected women who had answered positively to whether they had hypertension and/or proteinuria during one or more of their previous pregnancies (cases) and 200 women who had answered negatively (controls) were studied. The cases and controls were matched for age. The investigators were blinded to the allocation of cases and controls until data collection was finished. Main outcome measures Self-reported and actual prevalence of hypertensive pregnancy disorders and predictive value of self-reported hypertension and/or proteinuria in previous pregnancies. Results Clinical data were missing for 23.5% (94/400) of the participants (50 cases and 44 controls). A total of 80% (120/150) of cases and 57.1% (89/156) of controls had answered the question on whether or not they had high blood pressure and/or proteinuria during their pregnancies correctly (positive predictive value 0.800; negative predictive value 0.571). The proportion of false-positive cases declined with increasing age while the proportion of false-negative controls increased until 55 years of age. Conclusions We found good concordance between self-reported hypertension and/or proteinuria during previous pregnancies and actual clinical findings among the cases. However, there was a tendency towards under-reporting among controls.

Cardiovascular health and the modifiable burden of incident myocardial infarction: the Tromsø Study

Abstract: The American Heart Association has proposed an impact goal for the year 2020 to improve cardiovascular health by 20%. The objectives of the study were to assess the association between the proposed cardiovascular health metric score and incident myocardial infarction (MI) and to estimate the generalized impact fraction (GIF). The health metric score was derived from ideal levels of six cardiovascular risk factors from the population-based Tromso Study of 22,121 residents of Tromso, Norway aged 30 to 79 years, examined in 1994–95, 2001, and 2007–08. Incident events of MI were recorded from the date of enrollment in 1994–95 to the end of 2010. Adjudication of hospitalized and out-of hospital events was performed by an independent endpoints committee based on data from hospital and out-of hospital journals, autopsy records and death certificates. Cox proportional hazard regression was used to estimate hazard ratios (HR). GIF was calculated from age stratified analysis using a case-load weighted-sum method. Bootstrapping was used to estimate 95% simulation intervals. A total of 1652 MIs accrued over an average of 14.7 person-years of follow-up. Few men (0.96%) and women (3.6%) had ideal levels in all 6 metrics. 64.7% (men) and 55.7% (women) had ideal levels in 2 or 3 metrics. The age-adjusted HR per point increase in health score was 0.65 (95% confidence interval: 0.61, 0.70) in men and 0.59 (0.54, 0.64) in women. A shift of 30% of subjects from low score levels ≤3 to scores ≥4 was estimated to prevent 13.7% (11.2, 16.2) of incident MI in men and 15.9% (12.1, 19.4) in women. The association between the health metric score and MI indicate that close to 15% of incident MIs could be prevented by attainable and realistic improvements in the health metrics.

Clinically significant novel biomarkers for prediction of first ever myocardial infarction: the Tromsø Study.

Abstract: Background— Identification of individuals with high risk for first-ever myocardial infarction (MI) can be improved. The objectives of the study were to survey multiple protein biomarkers for association with the 10-year risk of incident MI and identify a clinically significant risk model that adds information to current common risk models. Methods and Results— We used an immunoassay platform that uses a sensitive, sample-efficient molecular counting technology to measure 51 proteins in samples from the fourth survey (1994) in the Tromso Study, a longitudinal study of men and women in Tromso, Norway. A case control design was used with 419 first-ever MI cases (169 females/250 males) and 398 controls (244 females/154 males). Of the proteins measured, 17 were predictors of MI when considered individually after adjustment for traditional risk factors either in men, women, or both. The 6 biomarkers adjusted for traditional risk factors that were selected in a multivariable model (odds ratios [OR] per standard deviation) using a stepwise procedure were apolipoprotein B/apolipoprotein A1 ratio (1.40), kallikrein (0.73), lipoprotein a (1.29), matrix metalloproteinase 9 (1.30), the interaction term IP-10/CXCL10×women (0.69), and the interaction term thrombospondin 4×men (1.38). The composite risk of these biomarkers added significantly to the traditional risk factor model with a net reclassification improvement of 14% ( P =0.0002), whereas the receiver operating characteristic area increased from 0.757 to 0.791, P =0.0004. Conclusions— Novel protein biomarker models improve identification of 10-year MI risk above and beyond traditional risk factors with 14% better allocation to either high or low risk group.

Genetic Variations in the Vitamin D Receptor Predict Type 2 Diabetes and Myocardial Infarction in a Community-Based Population: The Tromsø Study

Abstract: Background Though the associations between low serum 25-hydroxyvitamin D (25(OH)D) levels and health outcomes such as type 2 diabetes (T2D), myocardial infarction (MI), cancer, and mortality are well-studied, the effect of supplementation with vitamin D is uncertain. This may be related to genetic differences. Thus, rs7968585, a single nucleotide polymorphism (SNP) of the vitamin D receptor (VDR), has recently been reported as a predictor of composite health outcome. We therefore aimed to evaluate whether rs7968585 predicts separate clinical outcomes such as T2D, MI, cancer, and mortality in a community-based Norwegian population. Methods and Findings Measurements and DNA were obtained from the participants in the Tromso Study in 1994–1995, registered with the outcomes of interest and a randomly selected control group. The impact of the rs7968585 genotypes was evaluated with Cox proportional hazards. A total of 8,461 subjects were included among whom 1,054 subjects were registered with T2D, 2,287 with MI, 3,166 with cancer, and 4,336 with death. Mean follow-up time from birth was 60.8 years for T2D and MI, 61.2 years for cancer, while mean follow-up time from examination date was 16.5 years for survival. Mean serum 25(OH)D levels did not differ across the rs7968585 genotypes. With the major homozygote genotype as reference, the minor homozygote subjects had hazard ratios of 1.25 (95% CI 1.05–1.49) for T2D and 1.14 (1.02–1.28) for MI (P = 0.011 and 0.023, respectively, without the Bonferroni correction). No significant interaction between serum 25(OH)D status and the rs7968585 genotype was found for any of the endpoints. Conclusions The VDR-related SNP rs7968585 minor allele is a significant and positive predictor for T2D and possibly for MI. Since the functional mechanism of this SNP is not yet understood, and the association with T2D is reported for the first time, confirmatory studies are needed.

The DBP Phenotype Gc-1f/Gc-1f Is Associated with Reduced Risk of Cancer. The Tromsø Study

Abstract: Background and Objective In addition to its role as a transport protein, the vitamin D binding protein (DBP) may also affect lipid metabolism, inflammation and carcinogenesis. There are three common variants of the DBP, Gc1s (1s), Gc1f (1f), Gc2 (2) that result in six common phenotypes (1s/1s, 1s/1f, 1s/2, 1f/1f, 1f/2, and 2/2). These phenotypes can be identified by genotyping for the two single nucleotide polymorphisms rs7041 and rs4588 in the GC gene. The DBP variants have different binding coefficients for the vitamin D metabolites, and accordingly there may be important relations between DBP phenotypes and health. Methods DNA was prepared from subjects who participated in the fourth survey of the Tromso Study in 1994-1995 and who were registered with the endpoints myocardial infarction (MI), type 2 diabetes (T2DM), cancer or death as well as a randomly selected control group. The endpoint registers were complete up to 2010- 2013. Genotyping was performed for rs7041 and rs4588 and serum 25-hydroxyvitamin D (25(OH)D) was measured. Results Genotyping for rs7041 and rs4588 was performed successfully in 11 704 subjects. Among these, 1660 were registered with incident MI, 958 with T2DM, 2410 with cancer and 4318 had died. Subjects with the DBP phenotype 1f/1f had 23 – 26 % reduced risk of incident cancer compared to the 1s/1s and 2/2 phenotypes (P < 0.02, Cox regression with gender as covariate). Differences in serum 25(OH)D levels could not explain the apparent cancer protective effect of the DBP variant 1f. In addition to cancer and 25(OH)D, there were significant associations between DBP phenotype and body height, hip circumference and serum calcium. Conclusion There are important biological differences between the common DBP phenotypes. If the relation between the DBP variant 1f and cancer is confirmed in other studies, determination of DBP phenotype may have clinical importance.

Uric acid is associated with microalbuminuria and decreased glomerular filtration rate in the general population during 7 and 13 years of follow-up: The Tromsø Study

Abstract: The role of uric acid in development of renal dysfunction (RD) remains controversial. Earlier studies have reported inconsistent results, possibly because of their varying ability to adjust for confounding. The impact of longitudinal change in uric acid on renal outcome has not been assessed previously. We aimed to study the impact of change in serum uric acid (SUA) as well as baseline SUA on the development of RD. In a prospective cohort study, we assessed the associations between change in SUA during follow-up, baseline SUA and RD (defined as albumin-creatinine-ratio (ACR) ≥1.13 mg albumin/mmol creatinine and/or eGFR < 60 ml/min/1.73 m2) in a large cohort from a general population participating in the Tromso Study (n = 2637). Participants were stratified according to tertiles of change in SUA between baseline (1994/95) and follow-up 13 years later. (upper tertile: SUA increasing group, two lower tertiles: SUA non-increasing group). Logistic regression analysis was applied with RD and each component of RD after 7 and 13 years as the dependent variables. Adjustments were made for baseline eGFR, cardiovascular risk factors, and the use of antihypertensive drugs including diuretics. After excluding participants with RD at baseline, SUA increasers, compared to SUA non-increasers, had a doubled risk of RD after 7 years (odds ratio 2.00, (95 % CI 1.45, 2.75)). Odds ratio for RD in SUA increasers after 13 years was 2.18 (95 % CI 1.71, 2.79). The risk of developing ACR ≥1.13 mg/mmol alone was not significantly increased after 7 years (odds ratio 1.30 (95 % CI 0.90, 1.89), but after 13 years (odds ratio 1.43 (95 % CI 1.09, 1.86)). An increase in baseline SUA of 59 μmol/L (1 mg/dL) gave an odds ratio for RD after 13 years of 1.16 (95 % CI 1.04, 1.29). An increase in SUA during follow-up was associated with an increased risk of developing RD after 7 and 13 years.

Estimated and Measured GFR Associate Differently with Retinal Vasculopathy in the General Population

Abstract: © 2015 S. Karger AG, Basel Accepted manuscript version. Published version available at http://dx.doi.org/10.1159/000441092