Johann A. Sigurdsson

Body Configuration as a Predictor of Mortality: Comparison of Five Anthropometric Measures in a 12 Year Follow-Up of the Norwegian HUNT 2 Study

Background Distribution of body fat is more important than the amount of fat as a prognostic factor for life expectancy. Despite that, body mass index (BMI) still holds its status as the most used indicator of obesity in clinical work. Methods We assessed the association of five different anthropometric measures with mortality in general and cardiovascular disease (CVD) mortality in particular using Cox proportional hazards models. Predictive properties were compared by computing integrated discrimination improvement and net reclassification improvement for two different prediction models. The measures studied were BMI, waist circumference, hip circumference, waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR). The study population was a prospective cohort of 62,223 Norwegians, age 20–79, followed up for mortality from 1995–1997 to the end of 2008 (mean follow-up 12.0 years) in the Nord-Trøndelag Health Study (HUNT 2). Results After adjusting for age, smoking and physical activity WHR and WHtR were found to be the strongest predictors of death. Hazard ratios (HRs) for CVD mortality per increase in WHR of one standard deviation were 1.23 for men and 1.27 for women. For WHtR, these HRs were 1.24 for men and 1.23 for women. WHR offered the greatest integrated discrimination improvement to the prediction models studied, followed by WHtR and waist circumference. Hip circumference was in strong inverse association with mortality when adjusting for waist circumference. In all analyses, BMI had weaker association with mortality than three of the other four measures studied. Conclusions Our study adds further knowledge to the evidence that BMI is not the most appropriate measure of obesity in everyday clinical practice. WHR can reliably be measured and is as easy to calculate as BMI and is currently better documented than WHtR. It appears reasonable to recommend WHR as the primary measure of body composition and obesity.

Ethical dilemmas arising from implementation of the European guidelines on cardiovascular disease prevention in clinical practice. A descriptive epidemiological study.

Objective – Our first objective is to describe total, age- and gender-specific prevalences of subjects in a well-defined population for whom medical follow-up is indicated due to unfavourably high blood pressure and/or cholesterol levels, as defined by the 2003 European guidelines on cardiovascular disease prevention in clinical practice. Our second objective is to highlight scientific questions and ethical dilemmas relating to implementation of the guidelines. Design, setting, and participants – Cross-sectional population study comprising 62u2008104 adult Norwegians aged 20–79 years who participated in The Nord-Tröndelag Health Study 1995–97. Main outcome measures – Total, age- and gender-specific point prevalences of individuals with total cholesterol ≥5 mmol/l and/or systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg, or taking antihypertensive medication. Main results – In total, 76% of individuals aged 20–79 years have an “unfavourable” cardiovascular disease risk profile, according to guideline definitions. The point prevalence of individuals with cholesterol and/or blood pressure above the recommended cut-off points increases with age. By age 24, the prevalence reaches 50%. By age 49, it reaches 90%. Men below 50 years of age have higher combined risk prevalence than women. Conclusions and implications – Implementation of the 2003 European guidelines on CVD prevention would label a large majority of Norwegian adults as having unfavourably high cholesterol and/or blood pressure levels. The current biomedical standards appear to invalidate demographic health statistics. The theoretical basis on which the guidelines rest should thereby be scrutinized with regard to scientific methodology and consistency. Important ethical dilemmas arise at the point of guideline implementation, relating to risk labelling and medicalization, as well as resource allocation and sustainability within the healthcare system.

The clinical course of herpes zoster: A prospective study in primary care

Objectives: To determine the incidence of herpes zoster (HZ) and frequency of complications, mainly the incidence of postherpetic neuralgia (PHN).Design: Prospective follow-up study.Setting: Primary health care in Iceland.Main outcome measures: Incidence of HZ, age and sex distribution of patients and discomfort or pain 1, 3 and 12 months after the rash.Results: During an observation period of 229,547 person years, 462 episodes of acute zoster developed (incidence equals; 2.0/1,000/year) in 457 patients. End points were gained for all (100%) after 12 months follow up. Those still having pain after 12 months were followed further, 23 to 57 months more. Systemic acyclovir was used in less than 4%. A fourth of all HZ cases occurred in children and teenagers. PHN was rare in patients younger than 60 years of age; 2% and 1% experienced only mild pain at 3 and 12 months respectively. No patient had moderate or severe pain in this age group at these time points. In contrast pain was experienced by 19% and 8% of ...

Acute bronchitis in adults. How close do we come to its aetiology in general practice

OBJECTIVEnTo investigate how close we can come to the aetiology of acute bronchitis in adults in a primary care setting.nnnDESIGNnProspective study.nnnSETTINGnGeneral practice population in Gardabaer district, south-western Iceland.nnnSUBJECTSn140 patients > or = 16 years old who were diagnosed as having acute bronchitis during a two-year period (1992-1993).nnnMAIN OUTCOME MEASURESnLaboratory investigations (twice with a minimum four-week interval), used in general practice to analyse respiratory tract infections. They included serology for Chlamydia pneumoniae, Mycoplasma pneumoniae, respiratory tract viruses, and the level of C-reactive protein.nnnRESULTSnOf a total of 140 patients, two blood samples were taken on scheduled time in 113 patients. Serology confirmed recent infection in 18 (16%) of these patients. Only two (2%) had a bacterial infection (one C. pneumoniae, one M. pneumoniae). The others (84%) did not have a significant increase in antibody titres. Only four (4%) had C-reactive protein levels higher than 48 mg/l.nnnCONCLUSIONSnThe study indicates that it is difficult to come close to a precise aetiology with respect to infectious agents of acute bronchitis in general practice. We conclude that the disease is rarely caused by atypical bacteria such as C. pneumoniae and M. pneumoniae, and rarely caused by bacterial infections severe enough significantly to increase the level of C-reactive protein.

Is the use of cholesterol in mortality risk algorithms in clinical guidelines valid? Ten years prospective data from the Norwegian HUNT 2 study

Rationale, aims and objectives Many clinical guidelines for cardiovascular disease (CVD) prevention contain risk estimation charts/calculators. These have shown a tendency to overestimate risk, which indicates that there might be theoretical flaws in the algorithms. Total cholesterol is a frequently used variable in the risk estimates. Some studies indicate that the predictive properties of cholesterol might not be as straightforward as widely assumed. Our aim was to document the strength and validity of total cholesterol as a risk factor for mortality in a well-defined, general Norwegian population without known CVD at baseline. Methods We assessed the association of total serum cholesterol with total mortality, as well as mortality from CVD and ischaemic heart disease (IHD), using Cox proportional hazard models. The study population comprises 52 087 Norwegians, aged 20–74, who participated in the Nord-Trøndelag Health Study (HUNT 2, 1995–1997) and were followed-up on cause-specific mortality for 10 years (510 297 person-years in total). Results Among women, cholesterol had an inverse association with all-cause mortality [hazard ratio (HR): 0.94; 95% confidence interval (CI): 0.89–0.99 per 1.0 mmol L−1 increase] as well as CVD mortality (HR: 0.97; 95% CI: 0.88–1.07). The association with IHD mortality (HR: 1.07; 95% CI: 0.92–1.24) was not linear but seemed to follow a ‘U-shaped’ curve, with the highest mortality <5.0 and ≥7.0 mmol L−1. Among men, the association of cholesterol with mortality from CVD (HR: 1.06; 95% CI: 0.98–1.15) and in total (HR: 0.98; 95% CI: 0.93–1.03) followed a ‘U-shaped’ pattern. Conclusion Our study provides an updated epidemiological indication of possible errors in the CVD risk algorithms of many clinical guidelines. If our findings are generalizable, clinical and public health recommendations regarding the ‘dangers’ of cholesterol should be revised. This is especially true for women, for whom moderately elevated cholesterol (by current standards) may prove to be not only harmless but even beneficial.

Current European guidelines for management of arterial hypertension: Are they adequate for use in primary care? Modelling study based on the Norwegian HUNT 2 population

BackgroundPrevious studies indicate that clinical guidelines using combined risk evaluation for cardiovascular diseases (CVD) may overestimate risk. The aim of this study was to model and discuss implementation of the current (2007) hypertension guidelines in a general Norwegian population.MethodsImplementation of the current European Guidelines for the Management of Arterial Hypertension was modelled on data from a cross-sectional, representative Norwegian population study (The Nord-Trøndelag Health Study 1995-97), comprising 65,028 adults, aged 20-89, of whom 51,066 (79%) were eligible for modelling.ResultsAmong individuals with blood pressure ≥120/80 mmHg, 93% (74% of the total, adult population) would need regular clinical attention and/or drug treatment, based on their total CVD risk profile. This translates into 296,624 follow-up visits/100,000 adults/year. In the Norwegian healthcare environment, 99 general practitioner (GP) positions would be required in the study region for this task alone. The number of GPs currently serving the adult population in the study area is 87 per 100,000 adults.ConclusionThe potential workload associated with the European hypertension guidelines could destabilise the healthcare system in Norway, one of the worlds most long- and healthy-living nations, by international comparison. Large-scale, preventive medical enterprises can hardly be regarded as scientifically sound and ethically justifiable, unless issues of practical feasibility, sustainability and social determinants of health are considered.

Can individuals with a significant risk for cardiovascular disease be adequately identified by combination of several risk factors? Modelling study based on the Norwegian HUNT 2 population

Rationale, aims and objectives Clinicians are generally advised to consider several risk factors when evaluating patients cardiovascular disease (CVD) risk. Our aim was to study whether combined assessment of five traditional risk factors might help doctors demarcate a relatively distinct and manageable group of high-risk individuals. We selected five modifiable risk factors and estimated the proportion of a well-defined population with ‘unfavourable’ levels of at least two of them, as defined by four internationally renowned guidelines. The impact of including so-called ‘prehypertension’ among the risk factors was specifically addressed, and the results are discussed in a wider perspective. Material and methods Guideline implementation was modelled on data from a cross-sectional Norwegian population study comprising 62 104 adults aged 20–79 years (The Nord-Tröndelag Health Study 1995–7). Total, age- and gender-specific point prevalences of individuals with zero, one, two, three or more factors, in addition to established disease, were calculated. Results One single CVD risk factor was exhibited by 12.4% of the population; two factors by 21.5%; and three or more by 49.7%. Established CVD or diabetes mellitus was reported by 12.5%. In total, 83.7% of the population exhibited a risk or disease profile with at least two factors, if prehypertension was included. Conclusions If guideline recommendations are literally applied, as many as 84% of adults in Norway could exhibit two or more CVD or risk factors and thus be considered in need of individual, clinical attention. This challenges the widely held presumption that ‘the net will close’ around a manageable group of individuals-at-risk if several risk factors are jointly considered. As the finding of this study arises in one of the worlds most long- and healthy-living populations, it raises several practical as well as ethical questions.

Health problems in family practice: An Icelandic multicentre study

OBJECTIVEnTo establish epidemiological data on the health problems within family practice in Iceland by multicentre analysis of well-defined geographic areas.nnnDESIGNnProspective practice audit.nnnSUBJECTS AND SETTINGSnThirteen Icelandic health centres (HC) with computerized contact data from 1 January - 31 December 1988.nnnMAIN OUTCOME MEASURESnHealth problems during one year in a population, as perceived by health care providers.nnnRESULTSnA total of 176 384 health problems during one year in a population of 31 248, as perceived by the health care provider, were analysed. Musculoskeletal disorders accounted for 9.3% of all health problems (prevalence 210.6/1000 inhabitants), respiratory disorders 9.4% (189.9/1000), accidents 7.4% (203.2/1000), cardiovascular disorders 7.4% (112.0/1000) and mental disorders 6.1% (87.6/1000). The commonest single health problems were: hypertension, upper respiratory tract infections and non-articular rheumatism. The health problems accounting for the most frequent contacts were: mental disorders (4.0 contacts per individual per year), cardiovascular (3.7), and endocrine, nutrition and metabolic (3.2).nnnCONCLUSIONnProblem-oriented medical records from HCs, computerized in a uniform standardized way, can give extensive information about the content and burden of health problems in family practice and presumably public health. Our results are valuable because the population (the denominator) and the geographic study area are well defined. This information is an important part of clinical epidemiology and can be of great value for educators and health care planners.

The problems of antibiotic overuse

Acute otitis media among children and resistance development in the community n nAntibiotics provide little benefit for a large proportion of respiratory tract infections presenting in primary care. Prescribing antibiotics for self-limiting respiratory tract infections is nevertheless escalating and is probably the main reason for the emerging prevalence of antibiotic-resistant organisms in the community today [1]. The need has therefore been increasing to analyse the available data on antimicrobial usage in connection with the prevalence of antimicrobial-resistant organisms in order to help construct mathematical models predicting the likely outcomes of various antibiotic policy options [2]. n nNon-invasive pneumococcal infection, especially acute otitis media, is the main reason for antimicrobial prescriptions in the Western world [3]. Since the 1990s penicillin resistance of Streptococcus pneumoniae in Iceland has been a growing problem, and such resistance is still increasing, much faster than in most other European countries [3–5]. Over 35% of all pneumococci are now penicillin and macrolide non-susceptible [6]. This can probably be explained by the decades of higher antimicrobial usage in Iceland than in the other Nordic countries. Our own studies have shown that children under seven consumed about 20% of the total antimicrobial sales, and over 50% of these were prescribed only because of diagnosed acute otitis media. Furthermore, there was a causal connection between individual antimicrobial usage and the risk of carrying penicillin non-susceptible pneumococci in the first weeks after such treatment [3–5]. n nThe most interesting aspect of the studies, though, was discerning the interaction between selective antimicrobial pressure and the clonal dynamics of penicillin non-susceptible pneumococci in the study communities. This was done by comparing individually linked data with group-level data in relation to antibiotic use and resistance, which can be obscured by group-level ecological studies [7,8]. n nThe Icelandic studies also showed the likelihood of relapsing ear infections and the need for tympanostomy tube placements later in the communities with the highest antimicrobial consumption [9]. This may be explained by antimicrobials’ eradication of susceptible pneumococcus in the nasopharyngeal flora and interference with the natural balance of microbial species in the nasopharynx. This means that new strains can later emerge and increase the likelihood of new episodes of acute otitis media [3,10]. A tendency toward relapsing acute otitis because of superinfections by resistant strains may also be associated with decreased success in eradicating resistant pathogens from middle-ear fluid when otitis media is treated with antimicrobials [11]. The positive effect on antibiotic resistance and even infection rate following decreased antibiotic use may therefore outweigh the possible benefit of earlier symptom resolution attributed to antibiotic treatment in some cases. n nIn spite of several efforts to identify barriers against antibiotic overuse, more effort is needed to implement changes in this unfavourable development [3,7,8,12–14]. A phenomenological investigation in Iceland of why GPs prescribe antimicrobials in cases when there are no clear signs of bacterial infections, called “non-pharmacological prescriptions of antibiotics”, concludes that the principal reasons for such use of antibiotics are “the lack of stable doctor–patient relationships due to lack of continuity in medical care. Pressure from patients in a stressful society, the physicians work pressure, the physicians own personality, particularly the earnings incentive and service mentality and, last but not least, the physicians lack of confidence and uncertainty, resulting in use of antibiotic prescriptions as a coping strategy in an uncomfortable situation” [12]. n nThe large variations in antibiotic prescriptions indicate a need for further interventions to decrease unnecessary antibiotic use for respiratory tract infections. Antibiotics are frequently prescribed for children with unspecified upper respiratory tract infections and bronchitis, despite recommendations to the contrary. In a recent study from Sweden, it was shown that although fewer primary healthcare patients were diagnosed as having a respiratory tract infection, the proportion of patients being prescribed antibiotics nevertheless remained the same [15]. n nVaccines against the most common pathogens causing acute otitis media today, pneumococcus and Haemophilus influenzae, may lower the need for antimicrobial use in children. Implementation of these vaccines, which have not yet been decided for common use in children in Iceland, may give a good opportunity to deal with the resistance problem and diminish the demand for antibiotics. n nThe new (2008) NICE guidelines on respiratory tract infections (http://www.nice.org.uk/Guidance/CG69) aim to provide clear guidance on antibiotic management strategies for often self-limiting illnesses by giving evidence-based recommendations to diminish antimicrobial overuse in the community. National actions in Iceland have now followed these guidelines. It is hoped that we will see some positive changes, i.e. diminished development of resistance among the commonest respiratory pathogens in the community and even a lower infection rate through more prudent antimicrobial usage in the near future.

Otitis media, tympanostomy tube placement, and use of antibiotics. Cross-sectional community study repeated after five years.

Objective. To investigate potential links between antimicrobial drug use for acute otitis media (AOM) and tympanostomy tube placements, and the relationship between parental views and physician antimicrobial prescribing habits. Design. Cross-sectional community study repeated after five years. Subjects. Representative samples of children aged 1–6 years in four well-defined communities in Iceland, examined in 2003 (nu200a=u200a889) and 1998 (nu200a=u200a804). Main outcome measures. Prevalence of antimicrobial treatments for AOM, tympanostomy tube placements, and parental expectations of antimicrobial treatment. Results. Tympanostomy tubes had been placed at some time in 34% of children in 2003, as compared with 30% in 1998. A statistically significant association was found between tympanostomy tube placement rate and antimicrobial use for AOM in 2003. In the area where antimicrobial use for AOM was lowest in 1998, drug use had further diminished significantly. At the same time, the prevalence of tympanostomy tube placements had diminished from 26% to 17%. Tube placements had increased significantly, from 35% to 44%, in the area where antimicrobial use for AOM was highest. Parents in the area where antimicrobial consumption was lowest and narrow spectrum antimicrobials were most often used were less likely to be in favour of antimicrobial treatment. Conclusions. Comparison between communities showed a positive correlation between antimicrobial use for AOM and tympanostomy tube placements. The study supports a restrictive policy in relation to prescriptions of antibiotics for AOM. It also indicates that well-informed parents predict a restrictive prescription policy.