The impact of non-response weighting in health surveys for estimates on primary health care utilization.

BACKGROUND: Low response rates in health surveys may affect the representativeness and generalizability of results if non-response is systematically related to the indicator of interest. To account for such potential bias, weighting procedures are widely used with an overall aim to obtain less biased estimates. The aim of this study was to assess the impact of applying calibrated weights on prevalence estimates of primary health care utilization among respondents compared to the entire sample of a representative Danish survey of adults aged ≥16 years. METHODS: Registry-based 1-year prevalence data on health care utilization of chiropractor/physiotherapist, dentist and psychologist in 2016 were linked to the entire sample (n = 312 349), including respondents (n = 183 372), from the Danish National Health Survey in 2017. Calibrated weights, which applied information on e.g. sex, age, ethnic background, education and overall health service use were used to assess their impact on prevalence estimates among respondents. RESULTS: Across all included types of health care, weighting for non-response decreased prevalence estimates among respondents, which resulted in less biased estimates. For example, the overall 1-year prevalence of chiropractor/physiotherapist, dentist and psychologist utilization decreased from 19.1% to 16.9%, 68.4% to 62.5% and 1.9% to 1.8%, respectively. The corresponding prevalence in the entire sample was 16.5%, 59.4% and 1.7%. CONCLUSIONS: Applying calibrated weights to survey data to account for non-response reduces bias in primary health care utilization estimates. Future studies are needed to explore the possible impact of weighting on other health estimates.

The Danish health and morbidity surveys: study design and participant characteristics.

BACKGROUND: Reliable data from health surveys are essential to describe the status and trends in health indicators by means of information not available from official registers. In Denmark, nationally representative health surveys (the Danish Health and Morbidity Surveys) have been carried out among adults during the past three decades by the Danish National Institute of Public Health, University of Southern Denmark. The aim of the present study is to describe the study design of the three most recent surveys in 2010, 2013, and 2017, including the survey mode and response rates. METHODS: In 2010, 2013, and 2017, the samples (n = 25,000 each) were based on random sampling of individuals aged 16 years or older with a permanent residence in Denmark. A subsample of previously invited respondents was also re-invited in subsequent survey waves. Data were collected through self-administered questionnaires, yet with a concurrent mixed-mode approach, allowing for the invited individuals to complete either a web questionnaire or an identical paper questionnaire. In 2010 and 2013, survey invitations were sent by regular postal mail, whereas a secure electronical mail service, Digital Post, was used to invite the majority (90.1%) of the sample in 2017. RESULTS: The overall response rate decreased from 60.7% in 2010 to 57.1% in 2013 and 56.1% in 2017. Between 2010 and 2017 the response mode distribution for the web questionnaire increased markedly from 31.7 to 73.8%. The largest increase in the proportion which completed the web questionnaire was found in the oldest age group. CONCLUSIONS: Data from the Danish Health and Morbidity Surveys reveal an increasing proportion of the respondents to complete web questionnaires instead of paper questionnaires. Even though the response rate remained relatively stable in 2017, declining response rates is a major concern in health surveys. As the generalizability to the Danish population may be compromised by a low response rate, efforts to increase the response rate or keep it stable are crucial in future surveys. Thus, efforts should be made to ensure convenience and feasibility in relation to access to and the completion of survey (web) questionnaires.

Implications of the decline in adolescent drinking on the experience of alcohol-related consequences in the Nordic countries: A study based on data from the ESPAD project.

Aims: The aim of this study was to investigate: (1) whether self-reported acute alcohol-related consequences among adolescents in the Nordic countries have declined in concert with the decline in alcohol consumption; (2) whether the relationship between alcohol consumption and alcohol-related consequences has strengthened; and (3) whether the decline in alcohol-related consequences can be attributed to the decline in alcohol consumption. Methods: Data are from the European School Survey Project on Alcohol and Other Drugs (ESPAD) cross-sectional surveys in 2007, 2011 and 2015. Participants were students aged 15-16 years in 2007 (n = 16,035), 2011 (n = 14,765) and 2015 (n = 13,517). Alcohol consumption variables included lifetime and 12-month alcohol use, volume ethanol at last drinking occasion and heavy episodic drinking in the past 30 days. Self-reported acute alcohol-related consequences were measured as a sum index of experiencing the following at least once within the last 12 months: (1) an accident or injury; (2) being victimised by robbery or theft; or (3) had trouble with the police. Results: For all alcohol indicators, adolescent alcohol use decreased between 2007 and 2015. The highest prevalence estimates were found in Denmark, and here only the number of current drinkers decreased significantly. In addition, a decreasing trend in self-reported acute alcohol-related consequences was observed. We did not find a strengthening of the alcohol consumption consequences association from 2007 to 2015, except in Iceland. When all surveys were combined, the decrease in alcohol-related consequences could be explained by a decrease in alcohol consumption. Conclusions: Overall, adolescents aged 15-16 years exhibited decreasing trends in both alcohol consumption, less markedly in Denmark, and in our sum index of alcohol-related consequences between 2007 and 2015. Except for Iceland, we found no support for a strengthening of the alcohol-consequences association with declining drinking among adolescents.

Agreement between self-reported diseases from health surveys and national health registry data: a Danish nationwide study.

BACKGROUND: Agreement may be low when comparing self-reported diseases in health surveys with registry data. The aim of the present study was to examine the agreement between seven self-reported diseases among a representative sample of Danish adults aged ≥16 years and data from medical records. Moreover, possible associations with sociodemographic variables were examined. METHODS: Nationally representative data on self-reported current or previous diabetes, asthma, rheumatoid arthritis, osteoporosis, myocardial infarction, stroke and cancer, respectively, were derived from the Danish National Health Survey in 2017 (N=183 372). Individual-level data were linked to data on the same diseases from medical records in registries. Logistic regression models were used to explore potential associations between sociodemographic variables and total agreement. RESULTS: For all included diseases, specificity was >92% and sensitivity varied between 66% (cancer) and 95% (diabetes). Negative predictive value (NPV) was >96% for all diseases and positive predictive value (PPV) varied between 13% (rheumatoid arthritis) and 90% (cancer). Total agreement varied between 91% (asthma) and 99% (diabetes), whereas the kappa value was lowest for rheumatoid arthritis (0.21) and highest for diabetes (0.88). Sociodemographic variables were demonstrated to be significantly associated with total agreement for all diseases, with sex, age and educational level exhibiting the strongest associations. However, the directions of the associations were inconsistent across diseases. CONCLUSION: Overall, self-reported data were accurate in identifying individuals without the specific disease (ie, specificity and NPV). However, sensitivity, PPV and kappa varied greatly between diseases. These findings should be considered when interpreting similar results from surveys.

Health and Well-Being in Older Adults With a Surgically Closed or an Unrepaired Ventricular Septal Defect.

Background Older adults with a congenital ventricular septal defect (VSD) recently exhibited reduced heart rate variability and exercise capacity. It is unknown whether these findings affect health-related quality of life. Methods and Results Adults with VSDs and healthy controls, all concurrently included as part of another clinical study, completed the Danish National Health Survey questionnaire. Questionnaire data distributed to the general population were included and matched 10:1 with patients. Thirty patients with surgically closed VSDs (mean±SD age, 51±8 years), 300 adults from the general population (mean±SD age, 50±8 years), and 30 controls (mean±SD age, 51±9 years), as well as 30 patients with unrepaired VSDs (mean±SD age, 55±11 years), 300 adults from the general population (mean±SD age, 55±12 years), and 30 controls (mean±SD age, 55±10 years) completed the questionnaire. Educational level, social relations, and physical activity were comparable between groups. A larger proportion of patients with unrepaired VSDs compared with the general population experienced migraine (47% versus 24%; P=0.04), whereas more patients with surgically closed VSDs were affected by depression (13% versus 4%; P=0.02). For health-related quality of life, patients with surgically closed VSDs reported lower physical functioning (P<0.01), physical component summary (P<0.01), general health perception (P<0.01), and higher stress score (P=0.03) compared with the general population and healthy controls. Patients with unrepaired VSDs reported lower scores on physical functioning (P=0.03), bodily pain (P<0.01), and mental health (P=0.02), and a higher stress score (P=0.03), than controls. Conclusions Older patients with VSDs report lower self-perceived physical functioning, lower general health, and higher stress levels, all in line with previous findings, like lower exercise capacity and dysfunctional cognitive abilities, in adults with VSDs. Incessant follow-up is paramount, as neither successfully closed nor hemodynamically insignificant VSD is equivalent with untroubled healthy aging. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03684161.

Trends in social inequality in mortality in Denmark 1995-2019: the contribution of smoking- and alcohol-related deaths.

BACKGROUND: During the past decades, social inequality in mortality has increased in several countries, including Denmark. Modifiable risk factors, such as smoking and harmful alcohol consumption, have been suggested to moderate the association between socioeconomic position and health-related outcomes. The present study aims to investigate the contribution of smoking- and alcohol-related deaths to the trends in educational inequality in mortality in Denmark 1995-2019 among individuals aged 30-74 years. METHODS: Nationwide data on mortality and highest attained educational level divided into quartiles were derived from administrative registers. Alcohol-related mortality was directly estimated using information on alcohol-related deaths from death certificates. Smoking-related mortality was indirectly estimated using the Peto-Lopez method. The contribution of smoking- and alcohol-related deaths to the social inequality gap in mortality 1995-2019 was calculated. RESULTS: Alongside a decrease in all-cause mortality in Denmark 1995-2019, absolute differences in the mortality rate (per 100 000 person-year) between the lowest and the highest educational quartile increased from 494 to 607 among men and from 268 to 376 among women. Among both men and women, smoking- and alcohol-related deaths explained around 60% of the social inequality in mortality and around 50% of the increase in mortality inequality. CONCLUSION: Smoking and harmful alcohol consumption continue to be important risk factors and causes of social inequality in mortality, with around half of the increase in Denmark 1995-2019 being attributable to smoking- and alcohol-related deaths. Future healthcare planning and policy development should aim at reducing social inequality in modifiable health risk behaviours and their negative consequences.

Therapy-dependent inconsistencies in self-reported use of complementary and alternative medicine in the general population: findings from a longitudinal study.

OBJECTIVE: Information on the use of complementary and alternative medicine (CAM) in the general population is often collected by means of surveys, causing the reliability of data to rely on the memory accuracy of the respondent. The objective of this study was to examine the consistency in self-reported CAM use using data from two survey waves 4 years apart. DESIGN: Longitudinal study. SETTING/PARTICIPANTS: Data were obtained from the Danish Health and Morbidity Surveys. A nationally representative subsample of the individuals invited in 2013 was reinvited in 2017. In all, 2297 individuals (≥16 years) completed the self-administered questionnaire in both waves, including questions on for example, CAM use. MAIN OUTCOME MEASURES: The use of six different CAM therapies (acupuncture; craniosacral therapy; faith healing and/or clairvoyance; nutritional counselling; massage; osteopathy or other manipulative therapies; reflexology) was assessed by the response categories 'Yes, within the past 12 months', 'Yes, but previously than within the past 12 months' and 'No'. For each CAM therapy, an inconsistent response was defined as either the response combination (1) 'Yes, within the past 12 months' in 2013 and 'No' in 2017, or (2) 'Yes, within the past 12 months' or 'Yes, but previously than within the past 12 months' in 2013 and 'No' in 2017. RESULTS: The inconsistency percentages varied across CAM therapies. The highest levels of inconsistency for CAM use within the past 12 months were observed for nutritional counselling (64.9 %) and faith healing and/or clairvoyance (36.4 %). The lowest proportion of inconsistent responses was observed for acupuncture (18.3%). Overall, the same pattern was observed for lifetime CAM use. CONCLUSIONS: The results highlight the difficulty in obtaining reliable prevalence estimates on the use of CAM in the general population. Future studies should take these findings into account when interpreting similar analyses.

Trends in alcohol consumption among older adults in Denmark in the 21st century.

Background: Previous studies have indicated that the alcohol consumption among older Danish individuals has increased during the last three decades of the 20th century. However, the research is limited and, hence, the aim of the present article is to describe the trends and peculiarities in the development of the present situation in older people's drinking patterns in Denmark. Methods: Data were obtained from the Danish Health and Morbidity Survey (2005) and the Danish National Health Survey (2010, 2013, and 2017). Data used in this study were collected via self-administered questionnaires from random samples of the adult (≥ 16 years) Danish population. Response rates varied between 50.8% (2005) and 59.5% (2010). Drinking patterns are described using the following indicators: alcohol consumption during the past 12 months; alcohol consumption at least two days a week; mean number of standard drinks consumed in a typical week and heavy episodic drinking (at least monthly). Results are presented as percentages or means. Results: The prevalence of overall 12-month alcohol use in all individuals aged 60 years or older has slightly increased between 2010 (83.9%) and 2017 (85.2%). On the other hand, the prevalence of consuming alcohol at least twice a week has overall decreased slightly between 2010 (54.0%) and 2017 (52.0%) in the same age group. A decrease was also observed in the mean number of standard drinks consumed in a typical week, from 8.3 in 2010 to 7.0 in 2017. Additionally, the prevalence of consuming at least five standard drinks on one occasion at least monthly decreased markedly from 24.8% in 2005 to 14.8% in 2013 (the prevalence remained stable between 2013 and 2017). The trends in prevalence of various alcohol indicators varied by sex and age. Conclusions: The findings of this study suggest an overall decline in alcohol consumption among older Danes in the study period. The continuation of this trend will be the subject of future studies.

Consistency in Adults' Self-Reported Lifetime Use of Illicit Drugs: A Follow-Up Study Over 13 Years.

OBJECTIVE: Surveys are considered the best source of data available on the prevalence of illicit drug use in the general adult population. The objective of the present study was to examine the consistency in self-reported lifetime use of illicit drugs. METHOD: Data were obtained from the Danish Health and Morbidity Surveys. A nationally representative subsample of the individuals invited in 2000 was also invited to the subsequent three survey waves (2005, 2010, and 2013). The baseline sample size included 4,803 individuals between ages 16 and 64 years, of whom 3,053 completed a self-administered questionnaire. Recanting was defined as reporting lifetime use at baseline but denying such use in at least one of the subsequent survey waves. RESULTS: In all, 926 individuals reported lifetime use of cannabis in 2000 and 234 individuals reported lifetime use of hard drugs. After 5, 10, and 13 years, 10.2%, 15.6%, and 16.3% recanted their earlier reported use of cannabis, respectively. The prevalence increased with higher age. After 5 years, 20.4% recanted their earlier use of hard drugs. After 10 and 13 years, approximately 30% recanted their earlier use of hard drugs. This prevalence, too, increased with higher age. CONCLUSIONS: The validity of data on the lifetime use of illicit drugs derived from population surveys is questionable among adults in Denmark and perhaps in other countries. Future studies should take these findings into account when interpreting results, as such reporting patterns have considerable implications on the validity of the study results.