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Cohort Profile: The HUNT Study, Norway

The HUNT Study includes large total population-based cohorts from the 1980ies, covering 125 000 Norwegian participants; HUNT1 (1984-86), HUNT2 (1995-97) and HUNT3 (2006-08). The study was primarily set up to address arterial hypertension, diabetes, screening of tuberculosis, and quality of life. However, the scope has expanded over time. In the latest survey a state of the art biobank was established, with availability of biomaterial for decades ahead. The three population based surveys now contribute to important knowledge regarding health related lifestyle, prevalence and incidence of somatic and mental illness and disease, health determinants, and associations between disease phenotypes and genotypes. Every citizen of Nord-Trøndelag County in Norway being 20 years or older, have been invited to all the surveys for adults. Participants may be linked in families and followed up longitudinally between the surveys and in several national health- and other registers covering the total population. The HUNT Study includes data from questionnaires, interviews, clinical measurements and biological samples (blood and urine). The questionnaires included questions on socioeconomic conditions, health related behaviours, symptoms, illnesses and diseases. Data from the HUNT Study are available for researchers who satisfy some basic requirements (www.ntnu.edu/hunt), whether affiliated in Norway or abroad.

The prevalence of migraine and tension-type headaches among adolescents in Norway. The Nord-Trøndelag Health Study (Head-HUNT-Youth), a large population-based epidemiological study

The aim of this study was to examine the prevalence of headache and primary headache disorders like migraine and tension-type headaches among adolescents, and to explore the differences in headache prevalence and frequency by gender and age. This cross-sectional study was conducted in Nord-Trøndelag county, Norway, during the years 1995-97. In total, 8984 (88%) out of 10 202 invited adolescents aged 12-19 years participated in the youth part of the Nord-Trøndelag Health Study [Helseundersøkelsen i Nord-Trøndelag (HUNT)]. The total study population in this study consisted of 8255 individuals after exclusion of invalid questionnaires and students outside the target range of 13-18 years of age. The students completed a comprehensive questionnaire, and one of the questions was whether the students had experienced any headaches during the last 12 months. In addition, 5847 of these students were also subject to an interview in which they were asked whether they had experienced recurring headaches during the last year and, if so, were they classified as migraine (MI), tension-type headache (TTH) or non-classifiable headache. In the total questionnaire-based population, 76.8% reported having had headaches during the last 12 months (69.4% boys and 84.2% girls). Among those who also were interviewed, 29.1% reported having recurrent headaches (21.0% boys and 36.5% girls). The overall 1-year prevalence of migraine was 7%, of tension-type headache 18%, and of non-classifiable headache 4.8%. Higher prevalence rates were found for girls in all age groups and for all headache categories. The overall frequency of recurrent headaches did not vary significantly with age, but girls had significantly more frequent headaches than boys. We concluded that headache in general, and recurrent primary headache disorders like migraine and tension-type headaches, are common somatic complaints among Norwegian adolescents, especially among girls.

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.

Sex differences in lung vulnerability to tobacco smoking

Studies have indicated that females are more vulnerable to the deleterious effect of tobacco smoking than males. The current study aimed to investigate the associations between tobacco smoking and reported respiratory symptoms, self-rated health, and lung function by sex. In 1995–1997 65,225 subjects aged ≥20 yrs (71% of invited) attended for screening within the Nord-Trøndelag Health Study. Among these, 10,941 subjects selected randomly or because they reported having asthma or asthma-related symptoms, participated in the Bronchial Obstruction in Nord-Trøndelag study consisting of spirometry and a personal interview. Tobacco smoking was associated with increased prevalence of respiratory symptoms, reduced lung function, and lower score on global self-rated health (SRH). Adjusted for smoking burden and lung function, females had a higher risk for reporting respiratory symptoms and lower SRH compared with males. Further, smoking burden was associated with a larger relative reduction in expiratory lung function in females than in males. Females reported more symptoms and lower self-rated health compared with males with similar smoking burden. Even if smoking in females was associated with a larger reduction in per cent predicted lung function compared with males, this does not fully explain the higher symptom prevalence in females.

Reliability and validity of two frequently used self-administered physical activity questionnaires in adolescents

BackgroundTo create and find accurate and reliable instruments for the measurement of physical activity has been a challenge in epidemiological studies. We investigated the reliability and validity of two different physical activity questionnaires in 71 adolescents aged 13–18 years; the WHO, Health Behaviour in Schoolchildren (HBSC) questionnaire, and the International Physical Activity Questionnaire (IPAQ, short version).MethodsThe questionnaires were administered twice (8–12 days apart) to measure reliability. Validity was assessed by comparing answers from the questionnaires with a cardiorespiratory fitness test (VO2peak) and seven days activity monitoring with the ActiReg, an instrument measuring physical activity level (PAL) and total energy expenditure (TEE).ResultsIntraclass correlation coefficients for reliability for the WHO HBSC questionnaire were 0.71 for frequency and 0.73 for duration. For the frequency question, there was a significant difference between genders; 0.87 for girls and 0.59 for boys (p < 0.05). The intraclass correlation coefficients the IPAQ varied between 0.10 and 0.62 for the reliability. Spearman correlation coefficients for validity for both the WHO HBSC questionnaire and the IPAQ (recoded into low, moderate and high activity) measured against VO2peak were fair, ranging between 0.29 – 0.39. The WHO HBSC questionnaire measured against VO2peak for girls were acceptable, ranging between 0.30 – 0.55. Both questionnaires, except the walking question in IPAQ, showed a low correlation with PAL and TEE, ranging between 0.01 and 0.29.ConclusionThese data indicate that the WHO HBSC questionnaire had substantial reliability and were acceptable instrument for measuring cardiorespiratory fitness, especially among girls. None of the questionnaires however seemed to be a valid instrument for measuring physical activity compared to TEE and PAL in adolescents.

Forced spirometry reference values for Norwegian adults: the Bronchial Obstruction in Nord-Trondelag Study

The purpose of this study was to develop new prediction equations for flow/volume spirometry parameters in asymptomatic, never-smoking adults in Norway, and to assess any differences of these parameters when applying the new and most commonly used equation sets. Flow/volume spirometry was measured according to the American Thoracic Society criteria in 2,792 subjects aged > or = 20 yrs, randomly selected from participants in the Nord-Trøndelag Health Study. Ever-smokers and subjects with respiratory symptoms and/or diseases reported in this questionnaire were excluded. A total of 546 females and 362 males met the inclusion criteria and were included in the analyses. Most lung function variables were nonlinear by age and had to be transformed. After a plateau in younger adults, the variables declined by age. The reference values for forced expiratory volume in one second and forced vital capacity from the present study, were higher than those given by prediction equations from the European Community for Coal and Steel, but in closer agreement with later studies from Europe, Australia and the USA. Healthcare providers should be encouraged to reconsider their choice of prediction equations of spirometry in order to improve management of obstructive lung diseases.

Patterns of receptive and creative cultural activities and their association with perceived health, anxiety, depression and satisfaction with life among adults: the HUNT study, Norway

Background Cultural participation has been used both in governmental health policies and as medical therapy, based on the assumption that cultural activities will improve health. Previous population studies and a human intervention study have shown that religious, social and cultural activities predict increased survival rate. The aim of this study was to analyse the association between cultural activity and perceived health, anxiety, depression and satisfaction with life in both genders. Methods The study is based on the third population-based Nord-Trøndelag Health Study (2006–2008), including 50 797 adult participants from Nord-Trøndelag County, Norway. Data on cultural activities, both receptive and creative, perceived health, anxiety, depression and satisfaction with life were collected by comprehensive questionnaires. Results The logistic regression models, adjusted for relevant cofactors, show that participation in receptive and creative cultural activities was significantly associated with good health, good satisfaction with life, low anxiety and depression scores in both genders. Especially in men, attending receptive, rather than creative, cultural activities was more strongly associated with all health-related outcomes. Statistically significant associations between several single receptive, creative cultural activities and the health-related outcome variables were revealed. Conclusion This population-based study suggests gender-dependent associations between cultural participation and perceived health, anxiety, depression and satisfaction with life. The results support hypotheses on the effect of cultural activities in health promotion and healthcare, but further longitudinal and experimental studies are warranted to establish a reliable cause–effect relationship.

Intrauterine exposure to preeclampsia and adolescent blood pressure, body size, and age at menarche in female offspring.

OBJECTIVE To investigate whether female offspring of preeclamptic pregnancies have higher blood pressure, lower height, higher body mass index (BMI), and later age at menarche compared with offspring of normotensive pregnancies. METHODS Questionnaire information on age at menarche and measurements of blood pressure, height, and weight were collected among 4096 Norwegian girls 13–19 years old. Individual linkage to perinatal data registered at the national Medical Birth Registry allowed us to study the relationship of preeclampsia in the mother with adolescent blood pressure, body size, and age at menarche of daughters. RESULTS Maternal preeclampsia was associated in the female offspring with higher systolic (2.9 mm Hg difference, P < .001) and diastolic (1.7 mm Hg difference, P = .001) blood pressure during adolescence and higher weight (3.4 kg difference, P < .001) and BMI (22.6 versus 21.5, P < .001). After adjustment for adolescent BMI, the difference in systolic blood pressure was attenuated from 2.9 to 1.7 mm Hg (P = .017), and from 1.7 to 0.9 mm Hg (P = .08) for diastolic blood pressure. CONCLUSION Intrauterine exposure to preeclampsia was associated with increased adolescent blood pressure. The association may be causally related to adult hypertension but could also be confounded by higher BMI during adolescence.

Analgesic overuse among adolescents with headache The Head-HUNT-Youth Study

Objectives: To examine the association between the use of analgesics and primary headache disorders (i.e., migraine and tension-type headache) among adolescents in relation to age, gender, and headache frequency. Methods: This cross-sectional, population-based study was conducted in Norway from 1995 to 1997. The total study population consisted of 5,471 adolescents, 13 to 18 years of age, who were interviewed about their headache complaints and completed a comprehensive questionnaire including use of analgesics. Results: The prevalence of daily headache associated with analgesic use was 0.5%, with a higher rate for girls (0.8%) than for boys (0.2%). There was a significant association for both genders between analgesic use and headache, although most pronounced for migraine. There was a significant linear relationship between analgesic use and headache frequency. Analgesic use was more common among girls than boys and increased with age both for those with and those without headache. Conclusions: The use of analgesics is common among adolescents with headache, especially among girls. Although this study did not directly evaluate for medication-overuse headache, the trend of frequent analgesic use suggests this possibility. Parents and physicians should increase their awareness of potential analgesic overuse, especially among adolescents with frequent headache.

Physical exercise, sports, and lung function in smoking versus nonsmoking adolescents

Associations between adolescent smoking habits and exercise, particularly participation in sports and lung function were studied. All students aged 13–19 yrs in Nord-Trøndelag County, Norway, 1995–1997, were invited to join a cross-sectional study. Information on smoking habits and exercise was obtained by self-administered questionnaire. Spirometry was performed in accordance with American Thoracic Society standards. Of the 6,811 students (aged 13–18 yrs, without asthma), 2,993 (44%) reported never-smoking, and 1,342 (20%) reported current smoking (10% daily). Frequency of physical exercise was inversely associated with smoking, but participants in individual sports with lesser endurance, especially body-building and fighting sports, were more likely to be daily smokers than nonparticipants. Both daily (53%) and occasional smokers (43%) were more likely to have quit sports than never-smokers (26%). Never-smokers showed a positive dose-response between physical exercise and lung function (forced vital capacity and forced expiratory volume in one second, adjusted for age and height). No similar significant association was observed in daily smokers. These data suggest that smoking habits in different sports should be considered when promoting physical activity as smoking prevention, and sports organizations should include smoking prevention programmes. Adolescents with better lung function may self-select into sports; this possibility needs to be studied in a longitudinal design.