Tom Ivar Lund Nilsen

Change in body mass index and its impact on blood pressure: a prospective population study

BACKGROUND:Overweight and obesity increase the risk of elevated blood pressure, but the knowledge of the effect of weight change on blood pressure is sparse.OBJECTIVE:To investigate the association between change in body mass index (BMI) and change in diastolic blood pressure (DBP), systolic blood pressure (SBP), and hypertension status.DESIGN:Two population-based cross-sectional studies, one in 1984–86 and the other in 1995–97.SETTING:The Nord-Trøndelag Health Study (HUNT).PARTICIPANTS:We included 15 971 women and 13 846 men who were 20 y or older at the first survey, without blood pressure medication at both surveys and without diabetes, cardiovascular disease or dysfunction in daily life at baseline.MEASUREMENTS:Weight, height and blood pressure were measured standardised. Change in BMI was categorised as stable (initial BMI±0.1 kg/m2 each follow-up year), increased or decreased, and BMI was categorised by using World Health Organisations categorisation (underweight BMI: <18.5 kg/m2, normal weight BMI: 18.5–24.9 kg/m2, overweight BMI: 25.0–29.9 kg/m2, obesity BMI≥30 kg/m2).RESULTS:An increase in BMI and a decrease in BMI were significantly associated with increased and decreased SBP and DBP, respectively, compared to a stable BMI in both genders and all age groups, although the strongest effect was found among those who were 50 y and older. The adjusted odds ratio for having hypertension at HUNT 2 was 1.8 (95% confidence interval (CI): 1.5, 2.2) among women and 1.6 (95% CI: 1.4,1.8) among men aged 20–49 y who increased their BMI compared to those who had stable BMI. A similar, but weaker association was found among women and men aged 50 y or more. The mean change in both SBP and DBP was higher for those who changed BMI category from first to the second survey than for those who were in the same BMI class at both surveys.CONCLUSIONS:Our result supports an independent effect of change in BMI on change in SBP and DBP in both women and men, and that people who increase their BMI are at increased risk for hypertension.

Change in height, weight and body mass index: Longitudinal data from the HUNT Study in Norway

Objective:The aim of this study was to analyse changes in body weight and height, and the changes in the prevalence of overweight and obesity.Design:Prospective population based study with 11-year follow-up.Subjects:Norwegian men (n=21565) and women (n=24337) aged 20 years or more who participated in two health surveys, the first in 1984–1986 and the other in 1995–1997.Measurements:Height and weight were measured by using standardised procedures at both surveys, and we computed body mass index (BMI) as weight in kilo divided by the squared value of height in meters.Results:Participants who were younger than 50 years at the first survey showed a large increase in body weight, and men and women aged 20–29 years increased their weight with an average of 7.9 kg and 7.3 kg, respectively. Contradictory, participants who were 70 years or older had on average a weight loss. The prevalence of overweight (BMI=25.0–29.9 kg/m2) and obesity (BMI⩾30 kg/m2) increased between the surveys, especially in the youngest age groups. Overall, the proportion classified as obese increased from 6.7 to 15.5% among men and from 11.0 to 21.0% among women. Some of this increase was due to a reduction in height, which was most pronounced in the oldest age groups.Conclusion:During approximately 10 years, body weight increased in all age groups below 70 years, and the prevalence of overweight and obese persons was approximately 20% higher at the second survey compared with the first survey.

Peak Oxygen Uptake and Cardiovascular Risk Factors in 4631 Healthy Women and Men

INTRODUCTION Many studies suggest that cardiorespiratory fitness, measured as peak oxygen uptake (VO2peak), may be the single best predictor of cardiovascular morbidity and premature cardiovascular mortality. However, current reference values are either estimates of oxygen uptake or come from small studies, mainly of men. Therefore, the aims of this study were to directly measure VO2peak in healthy adult men and women and to assess the association with cardiovascular risk factor levels. METHODS A cross-sectional study of 4631 volunteering, free-living Norwegian men (n = 2368) and women (n = 2263) age 20-90 yr. The data collection was from June 2007 to June 2008. Participants were free from known pulmonary or cardiovascular disease. VO2peak was measured by ergospirometry during treadmill running. Associations (odds ratios, OR) with unfavorable levels of cardiovascular risk factors and a cluster of cardiovascular risk factors were assessed by logistic regression analysis. RESULTS Overall, mean VO2peak was 40.0 ± 9.5 mL·kg(-1)·min(-1). Women below the median VO2peak (<35.1 mL·kg(-1)·min(-1)) were five times (OR = 5.4, 95% confidence interval = 2.3-12.9) and men below the median (<44.2 mL·kg(-1)·min(-1)) were eight times (OR = 7.9, 95% confidence interval = 3.5-18.0) more likely to have a cluster of cardiovascular risk factors compared to those in the highest quartile of VO2peak (≥40.8 and ≥50.5 mL·kg(-1)·min(-1) in women and men, respectively). Each 5-mL·kg(-1)·min(-1) lower VO2peak corresponded to ∼56% higher odds of cardiovascular risk factor clustering. CONCLUSIONS These data represent the largest reference material of objectively measured VO2peak in healthy men and women age 20-90 yr. Even in people considered to be fit, VO2peak was clearly associated with levels of conventional cardiovascular risk factors.

Association between physical exercise, body mass index, and risk of fibromyalgia: longitudinal data from the Norwegian Nord-Trøndelag Health Study.

To examine the association between leisure time physical exercise, body mass index (BMI), and risk of fibromyalgia (FM).

A single weekly bout of exercise may reduce cardiovascular mortality: how little pain for cardiac gain? ‘The HUNT study, Norway’

Background The observation that exercise training reduces cardiovascular mortality is robust and consistent, but the amount and intensity of exercise that is required for risk reduction is not yet resolved. Methods We studied the association between the amount and intensity of exercise and cardiovascular mortality in 27 143 men and 28 929 women who were free from known cardiovascular disease at the beginning of follow-up between 1984 and 1986. The relative risk of death was calculated as the rate of death among participants within a given physical activity category compared with the rate of death in the reference category (no physical activity). We used Cox regression analysis to adjust for age and other potentially confounding factors. Results After 16 years (SD 4 years) of follow-up, 2946 men (10.8%) and 2486 women (8.6%) had died from ischaemic heart disease or stroke. A single weekly bout of exercise of high intensity reduced the risk of cardiovascular death, both in men [relative risk (RR) 0.61, 95% confidence interval (CI) 0.49–0.75], and women (RR 0.49, 95% CI 0.27–0.89), compared with those who reported no activity. There was no additional benefit from increasing the duration or the number of exercise sessions per week. The risk reduction related to exercise increased with increasing age in men, but not in women. Conclusion These results challenge the current recommendation that expenditure of at least 1000 kcal per week is required to achieve exercise-induced protection against premature cardiovascular mortality.

Thyrotropin Levels and Risk of Fatal Coronary Heart Disease: The HUNT Study

BACKGROUND Recent studies suggest that relatively low thyroid function within the clinical reference range is positively associated with risk factors for coronary heart disease (CHD), but the association with CHD mortality is not resolved. METHODS In a Norwegian population-based cohort study, we prospectively studied the association between thyrotropin levels and fatal CHD in 17,311 women and 8002 men without known thyroid or cardiovascular disease or diabetes mellitus at baseline. RESULTS During median follow-up of 8.3 years, 228 women and 182 men died of CHD. Of these, 192 women and 164 men had thyrotropin levels within the clinical reference range of 0.50 to 3.5 mIU/L. Overall, thyrotropin levels within the reference range were positively associated with CHD mortality (P for trend = .01); the trend was statistically significant in women (P for trend = .005) but not in men. Compared with women in the lower part of the reference range (thyrotropin level, 0.50-1.4 mIU/L), the hazard ratios for coronary death were 1.41 (95% confidence interval [CI], 1.02-1.96) and 1.69 (95% CI, 1.14-2.52) for women in the intermediate (thyrotropin level, 1.5-2.4 mIU/L) and higher (thyrotropin level, 2.5-3.5 mIU/L) categories, respectively. CONCLUSIONS Thyrotropin levels within the reference range were positively and linearly associated with CHD mortality in women. The results indicate that relatively low but clinically normal thyroid function may increase the risk of fatal CHD.

Maternal recall of breastfeeding duration twenty years after delivery

BackgroundStudies on the health benefits from breastfeeding often rely on maternal recall of breastfeeding. Although short-term maternal recall has been found to be quite accurate, less is known about long-term accuracy. The objective of this study was to assess the accuracy of long-term maternal recall of breastfeeding duration.MethodsIn a prospective study of pregnancy and birth outcome, detailed information on breastfeeding during the child’s first year of life was collected from a cohort of Norwegian women who gave birth in 1986–88. Among 374 of the participants, data on breastfeeding initiation and duration were compared to recalled data obtained from mailed questionnaires some 20 years later. Intraclass correlation coefficient (ICC), Bland-Altman plot, and Kappa statistics were used to assess the agreement between the two sources of data. Logistic regression was used to assess predictors of misreporting breastfeeding duration by more than one month.ResultsRecorded and recalled breastfeeding duration were strongly correlated (ICC=0.82, p < 0.001). Nearly two thirds of women recalled their breastfeeding to within one month. Recall data showed a modest median overestimation of about 2 weeks. There were no apparent systematic discrepancies between the two sources of information, but recall error was predicted by the age when infants were introduced to another kind of milk. Across categories of breastfeeding, the overall weighted Kappa statistic showed an almost perfect agreement (κ = 0.85, 95% confidence interval [CI] 0.82 – 0.88).ConclusionBreastfeeding duration was recalled quite accurately 20 years after mothers gave birth in a population where breastfeeding is common and its duration long.

Smoking and alcohol drinking in relation to risk of gastric cancer : A population-based, prospective cohort study

The relations between tobacco, alcohol and risk of gastric cancer need to be established, and any gain from preventive measures should be estimated. We conducted a population‐based, prospective cohort study in Nord‐Trondelag county in Norway. During 1984–1986, adult residents were invited to a health survey and they answered questionnaires that assessed exposure to tobacco and alcohol, together with potential confounding factors. The exposure assessment regarding alcohol was limited to a 14‐day period. New gastric cancers that occurred during follow‐up (1984–2002) were identified by linkage to the Norwegian Cancer Registry. Cox proportion hazards regression models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CI), adjusted for sex, education and body mass index. Follow‐up of 1,117,648 person‐years at risk among 69,962 cohort members revealed 251 gastric cancers, including 224 noncardia cancers. The risk was almost twice as high in daily smokers (HR = 1.88 [CI 95% = 1.33–2.67]) as in never smokers. Independent dose‐response relations were found with earlier age at initiation (p = 0.02), frequency (p = 0.00) and duration of smoking (p = 0.00). Attributable risk (AR) of gastric cancer among current smokers was 8.7/100,000 person‐years and the corresponding population AR was 18.4%. No statistically significant associations between various degrees of exposure to alcohol and risk of gastric cancer was revealed, but combined high use of cigarettes (>20/day) and alcohol (>5 occasions/14 days) increased the risk of noncardia gastric cancer nearly 5‐fold (HR = 4.90 [95% CI = 1.90–12.62]), compared to nonusers. It is concluded that smoking is a dose‐dependent risk factor for gastric cancer. Combined high exposure to smoking and alcohol further increases the risk. Successful preventive measures could considerably reduce the incidence of gastric cancer.

Recreational physical activity and risk of prostate cancer: A prospective population‐based study in Norway (the HUNT study)

Physical activity has been studied in relation to prostate cancer risk, but the findings have been inconclusive. We prospectively examined the association between self‐reported recreational physical activity and overall risk of prostate cancer, risk of advanced disease and risk of prostate cancer death in a cohort of 29,110 Norwegian men. Incident prostate cancers were obtained from the Norwegian Cancer Registry, and prostate cancer deaths were obtained from the national Cause of Death Registry. During 17 years of follow‐up, 957 incident cases were identified, 266 of them were advanced (i.e. metastases at diagnosis) and 354 of the incident cases died from prostate cancer. In multivariable analysis, frequency and duration of exercise were inversely associated with the risk of advanced prostate cancer (p for trend = 0.04 and 0.02). We computed a summary score that combined frequency, duration and intensity of exercise, and this score showed inverse associations with advanced prostate cancer risk and mortality (p for trend = 0.02 and 0.07). Compared to men who reported no activity, the relative risks (95% confidence intervals) among men in the highest category of physical exercise was 0.64 (0.43–0.95) for advanced prostate cancer and 0.67 (0.48–0.94) for prostate cancer death. We found no association between physical activity and overall risk of prostate cancer. We conclude that recreational physical exercise is associated with reduced risk of advanced prostate cancer and prostate cancer death.

A prospective study of lifestyle factors and the risk of pancreatic cancer in Nord-Trøndelag, Norway.

AbstractObjectives: Cancer of the pancreas is highly fatal and, despite extensive scrutiny, only cigarette smoking stands out as a likely causal agent in epidemiological studies. To explore to what extent different lifestyle factors are associated with the risk of pancreatic cancer, data from a large health screening survey in a county in Norway were analyzed. Methods: Our study included 31,000 men and 32,374 women initially free from any diagnosed cancer, and during 12 years of follow-up, 166 incident cases of pancreatic cancer were diagnosed at the Cancer Registry. Results: Compared with never smokers, we found a two-fold increased risk among current smokers, and a dose–response association with number of cigarettes (p for trend = 0.02 for both men and women) and with number of pack-years (p for trend = 0.02 for men and 0.01 for women). The risk among former smokers quitting more than 5 years before study entry was close to the risk of never smokers. Compared with persons who reported never or infrequently to be physically worn out after a days work, the relative risk (RR) among those who nearly always became worn out was 2.9 (95% confidence interval (CI) = 1.4–5.8) for men and 3.8 (95% CI = 1.6–9.2) for women. Divorced or separated men had a risk of 3.1 (95% CI = 1.3–7.2) compared with married men. We observed a higher risk among women in occupations of high socioeconomic status (RR = 2.5; 95% CI = 1.2–5.2), and among men occupied in farming, agriculture or forestry (RR = 2.1; 95% CI = 1.1–4.0), compared with persons in occupations of low socioeconomic status. Conclusions: Our results confirm the findings of previous studies that indicate a causal role of cigarette smoking in pancreatic cancer. Moreover, we found that the risk of former smokers may approach the risk of never smokers within a few years subsequent to quitting.