Merete Osler

The validity of the diagnosis of acute myocardial infarction in routine statistics: A comparison of mortality and hospital discharge data with the Danish MONICA registry

We analyzed the validity of the diagnosis of acute myocardial infarction (MI) in national registries by individual record linkage with the Danish MONICA registry. MI events were identified by record linkage between The National Hospital Registry and The National Death Registry. The sensitivity and specificity were estimated based on three different definitions of an MI event. For events with MI as the primary diagnosis or underlying cause of death the predictive value was 93.6% and sensitivity 77.6% when compared to DANMONICA definite or possible MI. Compared to DANMONICA, definite MI the predictive value was 75.0% and the sensitivity 92.8%. When secondary diagnosis and contributory cause of death were included, the sensitivity increased and the predictive value decreased only slightly. The combination of the national registries was found to be a valid and powerful tool for monitoring the population incidence of MI.

Food intake patterns and body mass index in observational studies.

OBJECTIVE: To review studies of patterns of food intake, as assessed by diet index, factor analysis or cluster analysis, and their associations with body mass index or obesity (BMI/Ob).DESIGN: Systematic literature review MEDLINE search with crosscheck of references.STUDIES: Thirty observational studies relating food intake patterns to anthropometric information were identified and reviewed. Food intake patterns were defined using a diet index, factor or cluster analysis in 12, nine and nine studies, respectively. Measures of body mass were made concurrently with the diet assessment in all studies, and only in a few cases were the primary outcomes related to BMI/Ob.RESULTS: The food intake patterns identified could, in most factor or cluster analysis studies, be categorised as: (a) meat, fatty, sweet or energy dense foods; (b) vegetables, fruit, whole grain and low-fat foods; or (c) by high alcohol consumption. The diet indexes were designed to capture a high diversity and/or food combinations matching the recommendations.The relationships with BMI/Ob were inconsistent—ten studies found that intake patterns, which we categorised as fatty, sweet or energy dense were positively associated with BMI/Ob, while similar patterns in four other studies were negatively associated with BMI. The significant associations between diet index score and BMI/Ob were consistently negative, while the associations between factor scores or cluster membership and BMI/Ob were less clear in terms of food intake pattern. Men and women had similar food intake patterns, but food intake patterns were less often positively associated with BMI/Ob in women. In 11 studies, there were no significant associations between food intake pattern and BMI/Ob.CONCLUSION: This review showed that no consistent associations could be identified between BMI or Ob and food intake patterns, derived from diet index, factor analysis or cluster analysis. However, the heterogeneity of food intake patterns identified by such analyses and the lack of gold standards for the application of these techniques hampers consistent analysis of a relation between food intake patterns and health.

Dietary patterns and mortality in Danish men and women: a prospective observational study

The analysis of dietary patterns emerged recently as a possible approach to examining diet-disease relation. We analysed the risk of all-cause and cardiovascular mortality associated with dietary patterns in men and women, while taking a number of potential confounding variables into account. Data were from a prospective cohort study with follow-up of total and cause-specific mortality. A random sample of 3698 men and 3618 women aged 30-70 years and living in Copenhagen County, Denmark, were followed from 1982 to 1998 (median 15 years). Three dietary patterns were identified from a twenty-eight item food frequency questionnaire, collected at baseline: (1) a predefined healthy food index, which reflected daily intakes of fruits, vegetables and wholemeal bread, (2) a prudent and (3) a Western dietary pattern derived by principal component analysis. The prudent pattern was positively associated with frequent intake of wholemeal bread, fruits and vegetables, whereas the Western was characterized by frequent intakes of meat products, potatoes, white bread, butter and lard. Among participants with complete information on all variables, 398 men and 231 women died during follow-up. The healthy food index was associated with reduced all-cause mortality in both men and women, but the relations were attenuated after adjustment for smoking, physical activity, educational level, BMI, and alcohol intake. The prudent pattern was inversely associated with all-cause and cardiovascular mortality after controlling for confounding variables. The Western pattern was not significantly associated with mortality. This study partly supports the assumption that overall dietary patterns can predict mortality, and that the dietary pattern associated with the lowest risk is the one which is in accordance with the current recommendations for a prudent diet.

Childhood Socioeconomic Position and Objectively Measured Physical Capability Levels in Adulthood: A Systematic Review and Meta-Analysis

Background Grip strength, walking speed, chair rising and standing balance time are objective measures of physical capability that characterise current health and predict survival in older populations. Socioeconomic position (SEP) in childhood may influence the peak level of physical capability achieved in early adulthood, thereby affecting levels in later adulthood. We have undertaken a systematic review with meta-analyses to test the hypothesis that adverse childhood SEP is associated with lower levels of objectively measured physical capability in adulthood. Methods and Findings Relevant studies published by May 2010 were identified through literature searches using EMBASE and MEDLINE. Unpublished results were obtained from study investigators. Results were provided by all study investigators in a standard format and pooled using random-effects meta-analyses. 19 studies were included in the review. Total sample sizes in meta-analyses ranged from N = 17,215 for chair rise time to N = 1,061,855 for grip strength. Although heterogeneity was detected, there was consistent evidence in age adjusted models that lower childhood SEP was associated with modest reductions in physical capability levels in adulthood: comparing the lowest with the highest childhood SEP there was a reduction in grip strength of 0.13 standard deviations (95% CI: 0.06, 0.21), a reduction in mean walking speed of 0.07 m/s (0.05, 0.10), an increase in mean chair rise time of 6% (4%, 8%) and an odds ratio of an inability to balance for 5s of 1.26 (1.02, 1.55). Adjustment for the potential mediating factors, adult SEP and body size attenuated associations greatly. However, despite this attenuation, for walking speed and chair rise time, there was still evidence of moderate associations. Conclusions Policies targeting socioeconomic inequalities in childhood may have additional benefits in promoting the maintenance of independence in later life.

Do we eat less fat, or just report so?

OBJECTIVE: To examine secular trends in diet reporting error.METHODS: Dietary information was obtained from 228 Danish men and women in 1987–88, and from 122 men and women in 1993–94.RESULTS: Bias in dietary reporting of energy and protein intake was assessed by comparing reported intake with intake data, estimated from 24 h nitrogen output, validated by administering P-aminobenzoic acid, and estimated 24 h energy expenditure. Total energy was under-reported more than energy from protein at both surveys, suggesting that energy from other nutrients, like fat and/or carbohydrate, must have been under-reported too. There was a greater under-reporting for energy than for protein in 1993–94 (29%) than in 1987–88 (15%). Obesity was positively associated with under-reporting, both in 1987–88 and in 1993–94.CONCLUSION: The higher macro-nutrient specific error in 1993–94 compared to 1987–88 may reflect a trend to increasingly omitting fat and/or carbohydrate-rich foods in dietary reporting. This may be a consequence of increased awareness of diet intake, which, in turn, may be related to intensified public health campaigns to reduce intake of fat and/or simple carbohydrate. These results may have consequences for our understanding of the apparent decline in dietary fat and associated health benefits.

Birthweight and mortality in adulthood: a systematic review and meta-analysis

BACKGROUND Small birth size may be associated with increased risk of cardiovascular diseases (CVD), whereas large birth size may predict increased risk of obesity and some cancers. The net effect of birth size on long-term mortality has only been assessed in individual studies, with conflicting results. METHODS The Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines for conducting and reporting meta-analysis of observational studies were followed. We retrieved 22 studies that assessed the association between birthweight and adult mortality from all causes, CVD or cancer. The studies were systematically reviewed and those reporting hazard ratios (HRs) and 95% confidence intervals (95% CIs) per kilogram (kg) increase in birthweight were included in generic inverse variance meta-analyses. RESULTS For all-cause mortality, 36,834 deaths were included and the results showed a 6% lower risk (adjusted HR = 0.94, 95% CI: 0.92-0.97) per kg higher birthweight for men and women combined. For cardiovascular mortality, the corresponding inverse association was stronger (HR = 0.88, 95% CI: 0.85-0.91). For cancer mortality, HR per kg higher birthweight was 1.13 (95% CI: 1.07-1.19) for men and 1.04 (95% CI: 0.98-1.10) for women (P(interaction) = 0.03). Residual confounding could not be eliminated, but is unlikely to account for the main findings. CONCLUSION These results show an inverse but moderate association of birthweight with adult mortality from all-causes and a stronger inverse association with cardiovascular mortality. For men, higher birthweight was strongly associated with increased risk of cancer deaths. The findings suggest that birthweight can be a useful indicator of processes that influence long-term health.

Causal Inference and Observational Research: The Utility of Twins.

Valid causal inference is central to progress in theoretical and applied psychology. Although the randomized experiment is widely considered the gold standard for determining whether a given exposure increases the likelihood of some specified outcome, experiments are not always feasible and in some cases can result in biased estimates of causal effects. Alternatively, standard observational approaches are limited by the possibility of confounding, reverse causation, and the nonrandom distribution of exposure (i.e., selection). We describe the counterfactual model of causation and apply it to the challenges of causal inference in observational research, with a particular focus on aging. We argue that the study of twin pairs discordant on exposure, and in particular discordant monozygotic twins, provides a useful analog to the idealized counterfactual design. A review of discordant-twin studies in aging reveals that they are consistent with, but do not unambiguously establish, a causal effect of lifestyle factors on important late-life outcomes. Nonetheless, the existing studies are few in number and have clear limitations that have not always been considered in interpreting their results. It is concluded that twin researchers could make greater use of the discordant-twin design as one approach to strengthen causal inferences in observational research.

Psychosocial, behavioural, and health determinants of successful smoking cessation: a longitudinal study of Danish adults

OBJECTIVE To examine the factors that determine whether or not smokers become long-term quitters, and to study whether determinants of successful cessation differ with levels of motivation to stop. DESIGN In a cohort of men and women, aged 30–60 years at first examination in 1982/1984, smoking behaviour was evaluated from questionnaires at baseline and at follow up 10 years later. SETTING County of Copenhagen, Denmark PARTICIPANTS 2554 subjects from the original sample of 4581 were successfully followed. This study deals with the 1365 subjects who were smokers at the first examination. MAIN OUTCOME MEASURE Smoking status (abstinent for one year or more) at follow up. RESULTS At follow up 15% of the baseline smokers had been abstinent for one year or more. In multivariate analysis, successful smoking cessation was associated with older age, high social status, low prior tobacco consumption, baseline motivation to stop smoking, and having a non-smoking spouse/cohabitant. The same result was obtained when the analyses were repeated separately for smokers with and without motivation to stop. CONCLUSIONS Smokers motivated to stop are more likely to quit and remain abstinent than smokers with no such motivation. Age, social status, spouse/cohabitant’s smoking behaviour, and the daily consumption of tobacco predict success in smoking cessation, irrespective of smokers’ former motivation to stop.

Socioeconomic position in early life, birth weight, childhood cognitive function, and adult mortality. A longitudinal study of Danish men born in 1953

Objective: To examine the relation between socioeconomic position in early life and mortality in young adulthood, taking birth weight and childhood cognitive function into account. Design: A longitudinal study with record linkage to the Civil Registration System and Cause of Death Registry. The data were analysed using Cox regression. Setting: The metropolitan area of Copenhagen, Denmark. Subjects: 7493 male singletons born in 1953, who completed a questionnaire with various cognitive measures, in school at age 12 years, and for whom birth certificates with data on birth and parental characteristics had been traced manually in 1965. This population was followed up from April 1968 to January 2002 for information on mortality. Main outcome measures: Mortality from all causes, cardiovascular diseases, and violent deaths. Results: Men whose fathers were working class or of unknown social class at time of birth had higher mortality rates compared with those whose fathers were high/middle class: hazard ratio 1.39 (95% CI 1.15 to 1.67) and 2.04 (95% CI 1.48 to 2.83) respectively. Birth weight and childhood cognitive function were both related to father’s social class and inversely associated with all cause mortality. The association between father’s social class and mortality attenuated (HRworking class1.30 (1.08 to 1.56); HRunkown class1.81 (1.30 to 2.52)) after control for birth weight and cognitive function. Mortality from cardiovascular diseases and violent deaths was also significantly higher among men with fathers from the lower social classes. Conclusion: The inverse association between father’s social class at time of birth and early adult mortality remains, however somewhat attenuated, after adjustment for birth weight and cognitive function.

Risk of hospital admission for COPD following smoking cessation and reduction: a Danish population study

Background: Little is known about the effects of changes in smoking habits on the subsequent risk of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the relationship between smoking cessation and reduction and admission to hospital for COPD in a general population sample. Methods: A total of 19 709 participants from three prospective population studies in Copenhagen were followed with record linkage for date of first hospital admission for COPD until 1998 (mean follow up 14 years). Heavy smokers (≥15 cigarettes/day) who reduced their tobacco consumption by at least 50% between the two initial examinations without quitting and smokers who stopped smoking during this time were compared with continuous heavy smokers using a Cox proportional hazards model. Results: During the follow up period 1260 subjects (741 men and 519 women) were admitted to hospital for COPD. After multivariate adjustment, quitting smoking was associated with a significant reduction in the risk of hospital admission. The relative hazard (HR) was 0.57 (95% confidence interval (CI) 0.33 to 0.99). Those who reduced smoking did not show a significantly lower risk of hospitalisation than continuing heavy smokers (HR 0.93 (95% CI 0.73 to1.18)). Exclusion of events during the first 5 study years, detailed adjustment for lung function, or restriction of analyses to participants with impaired pulmonary function did not reverse the observed trend. Conclusions: Self-reported smoking cessation is associated with a reduction in the risk of COPD morbidity of approximately 40%; the benefit of smoking reduction is questionable.