Comparing the sociodemographic characteristics of participants and non-participants in the population-based Tromsø Study.

BACKGROUND: Differences in the sociodemographic characteristics of participants and non-participants in population-based studies may introduce bias and reduce the generalizability of research findings. This study aimed to compare the sociodemographic characteristics of participants and non-participants of the seventh survey of the Tromsø Study (Tromsø7, 2015-16), a population-based health survey. METHODS: A total of 32,591 individuals were invited to Tromsø7. We compared the sociodemographic characteristics of participants and non-participants by linking the Tromsø7 invitation file to Statistics Norway, and explored the association between these characteristics and participation using logistic regression. Furthermore, we created a geographical socioeconomic status (area SES) index (low-SES, medium-SES, and high-SES area) based on individual educational level, individual income, total household income, and residential ownership status. We then mapped the relationship between area SES and participation in Tromsø7. RESULTS: Men, people aged 40-49 and 80-89 years, those who were unmarried, widowed, separated/divorced, born outside of Norway, had lower education, had lower income, were residential renters, and lived in a low-SES area had a lower probability of participation in Tromsø7. CONCLUSIONS: Sociodemographic differences in participation must be considered to avoid biased estimates in research based on population-based studies, especially when the relationship between SES and health is being explored. Particular attention should be paid to the recruitment of groups with lower SES to population-based studies.

Validity of self-reported educational level in the Tromsø Study.

BACKGROUND: Self-reported data on educational level have been collected for decades in the Tromsø Study, but their validity has yet to be established. AIM: To investigate the completeness and correctness of self-reported educational level in the Tromsø Study, using data from Statistics Norway. In addition, we explored the consequence of using these two data sources on educational trends in cardiometabolic diseases. METHODS: We compared self-reported and Statistics Norway-recorded educational level (primary, upper secondary, college/university <4 years, and college/university ⩾4 years) among 20,615 participants in the seventh survey of the Tromsø Study (Tromsø7, 2015-2016). Sensitivity, positive predictive value and weighted kappa were used to measure the validity of self-reported educational level in three age groups (40-52, 53-62, 63-99 years). Multivariable logistic regression was used to compare educational trends in cardiometabolic diseases between self-reported and Statistics Norway-recorded educational level. RESULTS: Sensitivity of self-reported educational level was highest among those with a college/university education of 4 years or more (⩾97% in all age groups and both sexes). Sensitivity for primary educational level ranged from 67% to 92% (all age groups and both sexes). The lowest positive predictive value was observed among women with a college/university education of 4 years or more (29-46%). Weighted kappa was substantial (0.52-0.59) among men and moderate to substantial (0.41-0.51) among women. Educational trends in the risk of cardiometabolic diseases were less pronounced when self-reported educational level was used. CONCLUSIONS: Self-reported educational level in Tromsø7 is adequately complete and correct. Self-reported data may produce weaker associations between educational level and cardiometabolic diseases than registry-based data.

Incidence and risk factors for major bleeding among patients undergoing percutaneous coronary intervention: Findings from the Norwegian Coronary Stent Trial (NORSTENT).

INTRODUCTION: Bleeding is a concern after percutaneous coronary intervention (PCI) and subsequent dual antiplatelet therapy (DAPT). We herein report the incidence and risk factors for major bleeding in the Norwegian Coronary Stent Trial (NORSTENT). MATERIALS AND METHODS: NORSTENT was a randomized, double blind, pragmatic trial among patients with acute coronary syndrome or stable coronary disease undergoing PCI during 2008-11. The patients (N = 9,013) were randomized to receive either a drug-eluting stent or a bare-metal stent, and were treated with at least nine months of DAPT. The patients were followed for a median of five years, with Bleeding Academic Research Consortium (BARC) 3-5 major bleeding as one of the safety endpoints. We estimated cumulative incidence of major bleeding by a competing risks model and risk factors through cause-specific Cox models. RESULTS: The 12-month cumulative incidence of major bleeding was 2.3%. Independent risk factors for major bleeding were chronic kidney disease, low bodyweight (< 60 kilograms), diabetes mellitus, and advanced age (> 80 years). A myocardial infarction (MI) or PCI during follow-up increased the risk of major bleeding (HR = 1.67, 95% CI 1-29-2.15). CONCLUSIONS: The 12-month cumulative incidence of major bleeding in NORSTENT was higher than reported in previous, explanatory trials. This analysis strengthens the role of chronic kidney disease, advanced age, and low bodyweight as risk factors for major bleeding among patients receiving DAPT after PCI. The presence of diabetes mellitus or recurrent MI among patients is furthermore a signal of increased bleeding risk. CLINICAL TRIAL REGISTRATION: Unique identifier NCT00811772; http://www.clinicaltrial.gov.

Pain sensitivity and analgesic use among 10,486 adults: the Tromsø study.

BACKGROUND: Increased pain sensitivity is a putative risk factor for chronic pain and consequently for analgesic use. Conversely, analgesic use may be a cause of increased pain sensitivity, e.g., through opioid-induced hyperalgesia. We aimed to study the association between pain sensitivity and analgesic use in a general population, and to test the hypothesis that increased baseline pain sensitivity is a risk factor for future persistent analgesic use. METHODS: The Tromsø Study (2007-08), a population-based health study, was linked with eight years of prescription data from the Norwegian Prescription Database. The cold pressor test was completed in 10,486 participants aged 30+ years, and we used cold pressor endurance time as a proxy measure of pain sensitivity. Cross-sectional associations with different measures of analgesic use were assessed. Furthermore, a cohort of 9,657 persons was followed for 4.5 years. RESULTS: In the cross-sectional analysis, increased pain sensitivity was associated with analgesic use; regular users of opioids alone were more pain sensitive than regular users of non-opioid analgesics. Increased baseline pain sensitivity was a risk factor for persistent analgesic use, i.e., using non-steroidal anti-inflammatory drugs, paracetamol, or opioids for ≥ 90 days and proportion-of-days-covered ≥ 40% (HR = 1.22, 95% CI 1.06-1.40), although not statistical significant after confounder adjustment. CONCLUSIONS: Increased pain sensitivity was associated with analgesic use in general, and reduced pain tolerance was found for both opioid and non-opioid analgesic users. The data suggest that hyperalgesia is an effect of analgesics, whereas pain tolerance has little impact on future analgesic use.

Persistent analgesic use and the association with chronic pain and other risk factors in the population-a longitudinal study from the Tromsø Study and the Norwegian Prescription Database.

PURPOSE: Analgesics are commonly used drugs. The long-term effectiveness is mostly unproven, while the risk of several serious adverse effects is well established. We aimed to estimate the prevalence and incidence of persistent analgesic use and the association with chronic pain and sociodemographic and comorbid risk factors. METHODS: The Tromsø Study is an epidemiological, prospective study of health and diseases. We linked the sixth wave (Tromsø 6, 2007-08, n = 12,981) with the Norwegian Prescription Database (NorPD, 2004-13). Persistent analgesic use was defined as the use of analgesics, i.e., either non-steroidal anti-inflammatory drugs, opioids or paracetamol, for ≥90 days with proportion-of-days-covered ≥40 %. The study design provided both cross-sectional and longitudinal data; a cohort of 11,905 persons was followed for 4.5 years. RESULTS: The prevalence of persistent analgesic use was 4 % in general and 10 % among those reporting chronic pain. The incidence rate of persistent analgesic use was 21 per 1000 person-years in general. Baseline chronic pain doubled the risk of incident persistent analgesic use (HR = 2.05, 95 % CI 1.80-2.33). The risk increased with increasing chronic pain severity, as measured by chronic pain duration, frequency, intensity, and number of body locations. Sociodemographic risk factors were older age, female sex, lower education, and most likely lower physical activity. Psychological distress was not a statistical significant risk factor. CONCLUSIONS: This study showed a relatively low prevalence of persistent analgesic use and that the majority of persons reporting chronic pain do not use analgesics persistently.

Analgesic use in a Norwegian general population: change over time and high-risk use--The Tromsø Study.

BACKGROUND: Increased use of analgesics in the population is a cause for concern in terms of drug safety. There is a paucity of population-based studies monitoring the change in use over time of both non-prescription (OTC) analgesics and prescription (Rx) analgesics. Although much is known about the risks associated with analgesic use, we are lacking knowledge on high-risk use at a population level. The purpose of this study was to estimate the prevalence of non-prescription and prescription analgesic use, change over time and the prevalence in the presence of potential contraindications and drug interactions in a general population. METHODS: A repeated cross-sectional study with data from participants (30-89 years) of the Tromsø Study in 2001-02 (Tromsø 5; N = 8039) and in 2007-08 (Tromsø 6; N = 12,981). Participants reported use of OTC and Rx analgesics and regular use of all drugs in the preceding four weeks. Change over the time period was analyzed with generalized estimating equations. The prevalence of regular analgesic use in persons with or without a clinically significant contraindication or drug interaction was determined in the Tromsø 6 population, and differences were tested with logistic regression. RESULTS: Analgesic use increased from 54 to 60% in women (OR = 1.24, 95% CI 1.15-1.32) and from 29 to 37% in men (OR = 1.39, 95% CI 1.27-1.52) in the time period; the increase was due to sporadic use of OTC analgesics. There was substantial regular use of analgesics in several of the contraindication categories examined; the prevalence of non-steroidal anti-inflammatory drugs was more than eight per cent among persons with chronic kidney disease, gastrointestinal ulcers, or high primary cardiovascular risk. About four per cent of the study population demonstrated at least one potential drug interaction with an analgesic drug. CONCLUSIONS: The use of analgesics increased in the time period due to an increase in the use of OTC analgesics. Analgesic exposure in the presence of contraindications or drug interactions may put patients at risk. Public and prescriber awareness about clinically relevant contraindications and drug interactions with analgesics need to be increased.

Separation of DNA-containing organelles from Toxoplasma gondii by CZE.

Toxoplasma gondii and other members of the family Apicomplexa have two organelles, in addition to the nucleus, that contain DNA. Herein is reported the separation of the DNA-carrying organelles from T. gondii tachyzoites, i.e. the mitochondrion and the apicoplast, by CZE. The cells were stained with SYTO9, a dye that exhibit fluorescence when interacting with double stranded nucleic acids (e.g. DNA) and disrupted by nitrogen cavitation. Following careful removal of the heavier cellular material, the remaining lysate was injected on a CE instrument and the DNA-containing organelles were detected by LIF. The mitochondrion had longer migration time than the apicoplast, and the migration times were comparable in the replicates. This method should potentially also work for other members of the Apicomplexa including Plasmodium falciparum.

Selective serotonin reuptake inhibitors in sewage influents and effluents from Tromsø, Norway.

An analytical method for quantification of the selective serotonin reuptake inhibitors (SSRIs) citalopram, sertraline, paroxetine, fluoxetine and fluvoxamine in sewage influents and effluents from selected sewage treatment plants (STPs) has been developed and validated. This quantification method is based on solid phase extraction of 2.5L samples, followed by liquid-liquid extraction for further sample clean up in order to minimize matrix effects during subsequent quantification. The samples were analysed on a high performance liquid chromatograph coupled to a triple quadrupole mass spectrometric detector using 0.1% ammonia in acetonitrile/water as mobile phase, with positive electrospray ionisation and multiple reaction monitoring for detection and quantification. 1-[3-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene)propyl]-pyrrolidine (N-7084) was used as internal standard for quantification. The recovery rates of the SSRIs ranged between 54 and 84%, and the method limit of quantification (MLQ) was between 120 and 290 pg/L for the target compounds. Samples were collected in July 2005 from three different STPs and a pump station in Tromsø, Northern Norway. Two of the STPs serve the University hospital and its psychiatric department, respectively, in addition to domestic sewage. SSRIs were detected in all samples collected. The concentrations varied greatly from below the MLQ to several hundreds ng/L. Concentrations in influents were higher compared to filtered effluents, indicating that SSRIs adsorb to particulate matter, are degraded by microorganisms, or degraded in other ways during the filtration process. However, more samples should be analysed before general conclusions can be drawn.