Does health literacy mediate the relationship between socioeconomic status and health related outcomes in the Belgian adult population?

BACKGROUND: Health literacy (HL) has been put forward as a potential mediator through which socioeconomic status (SES) affects health. This study explores whether HL mediates the relation between SES and a selection of health or health-related outcomes. METHODS: Data from the participants of the Belgian health interview survey 2018 aged 18 years or older were individually linked with data from the Belgian compulsory health insurance (n = 8080). HL was assessed with the HLS-EU-Q6. Mediation analyses were performed with health behaviour (physical activity, diet, alcohol and tobacco consumption), health status (perceived health status, mental health status), use of medicine (purchase of antibiotics), and use of preventive care (preventive dental care, influenza vaccination, breast cancer screening) as dependent outcome variables, educational attainment and income as independent variables of interest, age and sex as potential confounders and HL as mediating variable. RESULTS: The study showed that unhealthy behaviours (except alcohol consumption), poorer health status, higher use of medicine and lower use of preventive care (except flu vaccination) were associated with low SES (i.e., low education and low income) and with insufficient HL. HL partially mediated the relationship between education and health behaviour, perceived health status and mental health status, accounting for 3.8-16.0% of the total effect. HL also constituted a pathway by which income influences health behaviour, perceived health status, mental health status and preventive dental care, with the mediation effects accounting for 2.1-10.8% of the total effect. CONCLUSIONS: Although the influence of HL in the pathway is limited, our findings suggest that strategies for improving various health-related outcomes among low SES groups should include initiatives to enhance HL in these population groups. Further research is needed to confirm our results and to better explore the mediating effects of HL.

Anxiety and depression in people with post-COVID condition: a Belgian population-based cohort study three months after SARS-CoV-2 infection.

PURPOSE: Since the onset of the COVID-19 pandemic, most research has focused on the management of the acute symptoms of the disease. Yet some people tend to experience symptoms beyond the acute phase, defined as Post-COVID-19 Condition (PCC). This study aims to assess the impact of COVID-19 and PCC on anxiety and depression. METHODS: This is a prospective longitudinal cohort study among the Belgian adult population with recent SARS-CoV-2 infection for which contact tracing was initiated. A total of 3127 people were followed-up just after their infection and three months later (from April 2021 to January 2022). Anxiety and depression were assessed at the two stages using the GAD-7 (Generalized Anxiety Disorder) and the PHQ-9 (Patient Health Questionnaire). RESULTS: Three months after infection, participants with PCC (50%) had an increased probability of having both anxiety and depressive symptoms (p < 0.001). The proportion with anxiety and depressive symptoms at three months were significantly higher in people with PCC (11% and 19%) compared to people without persistent COVID symptoms (3.8% and 4.2%) and to a matched sub-sample not infected with SARS-CoV-2 (6.5% and 4.3%). Having at least one acute COVID-19 symptom (p < 0.001), experiencing financial loss following the infection (p < 0.001), and different PCC symptoms were associated with anxiety and depressive symptoms worsening over time. CONCLUSIONS: This study showed that three months after a SARS-CoV-2 infection, one in two people suffer from PCC with significant consequences for their mental health. Follow-up on mental health must therefore have an important place in people suffering from PCC.

Association between SARS-CoV-2 variants and post COVID-19 condition: findings from a longitudinal cohort study in the Belgian adult population.

BACKGROUND: While many studies on the determinants of post-COVID-19 conditions (PCC) have been conducted, little is known about the relationship between SARS-CoV-2 variants and PCC. This study aimed to assess the association between different SARS-CoV-2 variants and the probability of having PCC three months after the infection. METHODS: This study was a longitudinal cohort study conducted between April 2021 and September 2022 in Belgium. In total, 8,238 adults with a confirmed SARS-CoV-2 infection were followed up between the time of their infection and three months later. The primary outcomes were the PCC status three months post infection and seven PCC symptoms categories (neurocognitive, autonomic, gastrointestinal, respiratory, musculoskeletal, anosmia and/or dysgeusia, and other manifestations). The main exposure variable was the type of SARS-CoV-2 variants (i.e. Alpha, Delta, and Omicron), extracted from national surveillance data. The association between the different SARS-CoV-2 variants and PCC as well as PCC symptoms categories was assessed using multivariable logistic regression. RESULTS: The proportion of PCC among participants infected during the Alpha, Delta, and Omicron-dominant periods was significantly different and respectively 50%, 50%, and 37%. Participants infected during the Alpha- and Delta-dominant periods had a significantly higher odds of having PCC than those infected during the Omicron-dominant period (OR = 1.61, 95% confidence interval [CI] = 1.33-1.96 and OR = 1.73, 95%CI = 1.54-1.93, respectively). Participants infected during the Alpha and Delta-dominant periods were more likely to report neurocognitive, respiratory, and anosmia/dysgeusia symptoms of PCC. CONCLUSIONS: People infected during the Alpha- and Delta-dominant periods had a higher probability of having PCC three months after infection than those infected during the Omicron-dominant period. The lower probability of PCC with the Omicron variant must also be interpreted in absolute figures. Indeed, the number of infections with the Omicron variant being higher than with the Alpha and Delta variants, it is possible that the overall prevalence of PCC in the population increases, even if the probability of having a PCC decreases.

Post COVID-19 condition and health-related quality of life: a longitudinal cohort study in the Belgian adult population.

BACKGROUND: Since the onset of the COVID-19 pandemic, most research has focused on the acute phase of COVID-19, yet some people experience symptoms beyond, referred to as post COVID-19 conditions (PCC). However, evidence on PCC and its impacts on health-related quality of life (HRQoL) is still scarce. This study aimed to assess the impact of COVID-19 and PCC on HRQoL. METHODS: This is a longitudinal cohort study of the Belgian adult population with recent SARS-CoV-2 infection. In total, 5,727 people were followed up between the time of their infection and three months later. HRQoL was measured with the EQ-5D-5L questionnaire before and during the infection and three months later. Linear mixed regression models were built to assess the longitudinal association between participants' characteristics and the evolution of their HRQoL. RESULTS: This study found a significant decline in HRQoL during the SARS-CoV-2 infection in comparison to the situation before (ß=-9.91, 95%CI=-10.13;-9.85), but no clinically important difference three months after the infection compared to the situation before, except among people reporting PCC (ß=-11.15, 95%CI=-11.72;-10.51). The main symptoms of PCC with a significant negative impact on the different dimensions of HRQoL were fatigue/exhaustion (21%), headache (11%), memory problems (10%), shortness of breath (9%), and joint (7%) or muscle pain (6%). The dimension of HRQoL most negatively affected by several PCC symptoms was pain/discomfort. CONCLUSIONS: With the growing number of people infected with SARS-CoV-2, PCC and its impact on HRQoL are becoming important public health issues. To allow people with PCC to recover and to limit its detrimental impact on HRQoL, it is essential to manage its various heterogeneous symptoms using a multidisciplinary approach.

The impact of multimorbidity patterns on health-related quality of life in the general population: results of the Belgian Health Interview Survey.

BACKGROUND: Chronic diseases and multimorbidity are a major cause of disease burden-for patients, caregivers, and society. Little is known however about potential interaction effects between specific disease combinations. Besides an additive effect, the presence of multiple conditions could also act synergistically or antagonistically regarding the impact on patients' health-related quality of life (HRQoL). The aim was to estimate the impact of coexisting chronic diseases on HRQoL of the adult general Belgian population. METHODS: The Belgian Health Interview Survey 2018 provided data on self-reported chronic conditions and HRQoL (EQ-5D-5L) for a nationally representative sample. Linear mixed models were used to analyze two-way and three-way interactions of disease combinations on HRQoL. RESULTS: Multimorbidity had a prevalence of 46.7% (≥ 2 conditions) and 29.7% (≥ 3 conditions). HRQoL decreased considerably with the presence of multiple chronic diseases. 14 out of 41 dyad combinations and 5 out of 13 triad combinations showed significant interactions, with a dominant presence of negative/synergistic effects. Positive/antagonistic effects were found in more subjective chronic diseases such as depression and chronic fatigue. Conditions appearing the most frequently in significant disease pair interactions were dorsopathies, respiratory diseases, and arthropathies. CONCLUSIONS: Diverse multimorbidity patterns, both dyads and triads, were synergistically or antagonistically associated with lower HRQoL. Tackling the burden of multimorbidity is needed, especially because most disease combinations affect each other synergistically, resulting in a greater reduction in HRQoL. Further knowledge about those multimorbidity patterns with a greater impact on HRQoL is needed to better understand disease burden beyond mortality and morbidity data.

Belgian population norms for the EQ-5D-5L, 2018.

PURPOSE: Health-related quality of life outcomes are increasingly used to monitor population health and health inequalities and to assess the (cost-) effectiveness of health interventions. The EQ-5D-5L has been included in the Belgian Health Interview Survey, providing a new source of population-based self-perceived health status information. This study aims to estimate Belgian population norms for the EQ-5D-5L by sex, age, and region and to analyze its association with educational attainment. METHODS: The BHIS 2018 provided EQ-5D-5L data for a nationally representative sample of the Belgian population. The dimension scores and index values were analyzed using logistic and linear regressions, respectively, accounting for the survey design. RESULTS: More than half of respondents reported problems of pain/discomfort, while over a quarter reported problems of anxiety/depression. The average index value was 0.84. Women reported more problems on all dimensions, but particularly on anxiety/depression and pain/discomfort, resulting in significantly lower index values. Problems with mobility, self-care, and usual activities showed a sharp increase after the age of 80 years. Consequently, index values decreased significantly by age. Lower education was associated with a higher prevalence of problems for all dimensions except anxiety/depression and with a significantly lower index value. CONCLUSION: This paper presents the first nationally representative Belgian population norms using the EQ-5D-5L. Inclusion of the EQ-5D in future surveys will allow monitoring over time of self-reported health, disease burden, and health inequalities.

Predictors of nursing home admission in the older population in Belgium: a longitudinal follow-up of health interview survey participants.

BACKGROUND: This study examines predictors of nursing home admission (NHA) in Belgium in order to contribute to a better planning of the future demand for nursing home (NH) services and health care resources. METHODS: Data derived from the Belgian 2013 health interview survey were linked at individual level with health insurance data (2012 tot 2018). Only community dwelling participants, aged ≥65 years at the time of the survey were included in this study (n = 1930). Participants were followed until NHA, death or end of study period, i.e., December 31, 2018. The risk of NHA was calculated using a competing risk analysis. RESULTS: Over the follow-up period (median 5.29 years), 226 individuals were admitted to a NH and 268 died without admission to a NH. The overall cumulative risk of NHA was 1.4, 5.7 and 13.1% at respectively 1 year, 3 years and end of follow-up period. After multivariable adjustment, higher age, low educational attainment, living alone and use of home care services were significantly associated with a higher risk of NHA. A number of need factors (e.g., history of falls, suffering from urinary incontinence, depression or Alzheimer's disease) were also significantly associated with a higher risk of NHA. On the contrary, being female, having multimorbidity and increased contacts with health care providers were significantly associated with a decreased risk of NHA. Perceived health and limitations were both significant determinants of NHA, but perceived health was an effect modifier on limitations and vice versa. CONCLUSIONS: Our findings pinpoint important predictors of NHA in older adults, and offer possibilities of prevention to avoid or delay NHA for this population. Practical implications include prevention of falls, management of urinary incontinence at home and appropriate and timely management of limitations, depression and Alzheimer's disease. Focus should also be on people living alone to provide more timely contacts with health care providers. Further investigation of predictors of NHA should include contextual factors such as the availability of nursing-home beds, hospital beds, physicians and waiting lists for NHA.

QALY losses for chronic diseases and its social distribution in the general population: results from the Belgian Health Interview Survey.

BACKGROUND: The burden of chronic diseases is rapidly rising, both in terms of morbidity and mortality. This burden is disproportionally carried by socially disadvantaged population subgroups. Quality-adjusted life years (QALYs) measure the impact of disease on mortality and morbidity into a single index. This study aims to estimate the burden of chronic diseases in terms of QALY losses and to model its social distribution for the general population. METHODS: The Belgian Health Interview Survey 2013 and 2018 provided data on self-reported chronic conditions for a nationally representative sample. The annual QALY loss per 100,000 individuals was calculated for each condition, incorporating disease prevalence and health-related quality of life (HRQoL) data (EQ-5D-5L). Socioeconomic inequalities, based on respondents' socioeconomic status (SES), were assessed by estimating population attributable fractions (PAF). RESULTS: For both years, the largest QALY losses were observed in dorsopathies, arthropathies, hypertension/high cholesterol, and genitourinary problems. QALY losses were larger in women and in older individuals. Individuals with high SES had consistently lower QALY loss when facing a chronic disease compared to those with low SES. In both years, a higher PAF was found in individuals with hip fracture and stroke. In 2013, the health inequality gap amounts to 33,731 QALYs and further expanded to 42,273 QALYs in 2018. CONCLUSION: Given that chronic diseases will rise in the next decades, addressing its burden is necessary, particularly among the most vulnerable (i.e. older persons, women, low SES). Interventions in these target groups should get priority in order to reduce the burden of chronic diseases.

Unit Response and Costs in Web Versus Face-To-Face Data Collection: Comparison of Two Cross-sectional Health Surveys.

BACKGROUND: Potential is seen in web data collection for population health surveys due to its combined cost-effectiveness, implementation ease, and increased internet penetration. Nonetheless, web modes may lead to lower and more selective unit response than traditional modes, and this may increase bias in the measured indicators. OBJECTIVE: This research assesses the unit response and costs of a web study versus face-to-face (F2F) study. METHODS: Alongside the Belgian Health Interview Survey by F2F edition 2018 (BHISF2F; net sample used: 3316), a web survey (Belgian Health Interview Survey by Web [BHISWEB]; net sample used: 1010) was organized. Sociodemographic data on invited individuals was obtained from the national register and census linkages. Unit response rates considering the different sampling probabilities of both surveys were calculated. Logistic regression analyses examined the association between mode system and sociodemographic characteristics for unit nonresponse. The costs per completed web questionnaire were compared with the costs for a completed F2F questionnaire. RESULTS: The unit response rate is lower in BHISWEB (18.0%) versus BHISF2F (43.1%). A lower response rate was observed for the web survey among all sociodemographic groups, but the difference was higher among people aged 65 years and older (15.4% vs 45.1%), lower educated people (10.9% vs 38.0%), people with a non-Belgian European nationality (11.4% vs 40.7%), people with a non-European nationality (7.2% vs 38.0%), people living alone (12.6% vs 40.5%), and people living in the Brussels-Capital (12.2% vs 41.8%) region. The sociodemographic characteristics associated with nonresponse are not the same in the 2 studies. Having another European (OR 1.60, 95% CI 1.20-2.13) or non-European nationality (OR 2.57, 95% CI 1.79-3.70) compared to a Belgian nationality and living in the Brussels-Capital (OR 1.72, 95% CI 1.41-2.10) or Walloon (OR 1.47, 95% CI 1.15-1.87) regions compared to the Flemish region are associated with a higher nonresponse only in the BHISWEB study. In BHISF2F, younger people (OR 1.31, 95% CI 1.11-1.54) are more likely to be nonrespondents than older people, and this was not the case in BHISWEB. In both studies, lower educated people have a higher probability of being nonrespondent, but this effect is more pronounced in BHISWEB (low vs high education level: Web, OR 2.71, 95% CI 2.21-3.39 and F2F OR 1.70, 95% CI 1.48-1.95). The BHISWEB study had a considerable advantage; the cost per completed questionnaire was almost 3 times lower (€41 [US $48]) compared with F2F data collection (€111 [US $131]). CONCLUSIONS: The F2F unit response rate was generally higher, yet for certain groups the difference between web and F2F was more limited. Web data collection has a considerable cost advantage. It is therefore worth experimenting with adaptive mixed-mode designs to optimize financial resources without increasing selection bias (eg, only inviting sociodemographic groups who are keener to participate online for web surveys while continuing to focus on increasing F2F response rates for other groups).

Food insecurity and its association with changes in nutritional habits among adults during the COVID-19 confinement measures in Belgium.

OBJECTIVE: To assess food insecurity and its association with changes in nutritional habits among Belgian adults during confinement due to COVID-19. DESIGN: Three cross-sectional online health surveys were conducted during March-May 2020. Multinomial logistic regression models were used to determine associations between self-reported changes in fruit, vegetable, soft drink and sweet and salted snack consumption or weight as dependent variables and food insecurity indicators as independent variables, adjusted for gender, household composition, educational attainment and household income. SETTING: Belgium. PARTICIPANTS: In total, 8640 adults recruited by convenience sampling. RESULTS: About 10·4 % of Belgians often or sometimes feared food shortages, 5·0 % were often or sometimes short of food without money to buy more and 10·3 % often or sometimes could not afford to eat a healthy diet during confinement. These percentages were highest among single-parent families (26·7, 14·4 and 23·4 %, respectively). Adults who often or sometimes feared that food would run out during confinement had significantly higher odds of decreased v. unchanged fruits (3·53; 95 % CI = 2·06, 6·05) and vegetables (5·42; 95 % CI = 2·90, 10·11) consumption and significantly higher odds of increased v. unchanged soft drink consumption (3·79; 95 % CI = 2·20, 6·54). Similar results were found for adults who often or sometimes ran out of food and for adults who often or sometimes were not able to afford a healthy diet. CONCLUSION: Food insecurity during the COVID-19 confinement measures in Belgium was associated with adverse changes in most dietary behaviours. A strong government response is needed to tackle malnutrition and food insecurity to protect public health from ongoing and future pandemics.

Mental health, compliance with measures and health prospects during the COVID-19 epidemic: the role of health literacy.

BACKGROUND: The importance of health literacy in dealing with the COVID-19 epidemic has been emphasized but scarcely addressed empirically. In this study, the association of health literacy with mental health, compliance with COVID-19 preventive measures and health prospects was assessed in a Belgian context. METHODS: Data were extracted from the third of a series of cross-sectional online COVID-related surveys (n = 32,794). Data collection took place for 1 week starting the 28th of May 2020. People residing in Belgium and aged 18 years or older could participate. Data were collected on sociodemographic background, health literacy, multimorbidity, mental health (depression, anxiety, sleeping disorder, vitality), knowledge about COVID-19, compliance with COVID-19 measures (hygiene, physical distance, covering mouth and nose on public transport and in places where physical distance cannot be respected), and health prospects (risk for health when returning to normal life and possibility of infection). Prevalence Ratio (PR) of poor mental health, non-compliance with the measures and health prospects in relation to health literacy were calculated using Poisson regressions. RESULTS: People showing sufficient health literacy were less likely to suffer from anxiety disorders (PR = 0.47, 95% CI = [0.42-0.53]), depression (PR = 0.46, 95% CI = [0.40-0.52]) and sleeping disorders (PR = 0.85, 95% CI = [0.82-0.87]), and more likely to have optimal vitality (PR = 2.41, 95% CI = [2.05-2.84]) than people with low health literacy. They were less at risk of not complying with the COVID-19 measures (PR between 0.60 and 0.83) except one (covering mouth and nose in places where physical distance cannot be respected). Finally, they were less likely to perceive returning to normal life as threatening (PR = 0.70, 95% CI = [0.65-0.77]) and to consider themselves at risk of an infection with COVID-19 (PR = 0.75, 95% CI = [0.67-0.84]). The associations remained significant after controlling for COVID-19 knowledge and multimorbidity. CONCLUSIONS: These results suggest that health literacy is a crucial factor in managing the COVID-19 epidemic and offer a perspective for future studies that target health literacy in the context of virus outbreaks.

Validity of self-reported mammography uptake in the Belgian health interview survey: selection and reporting bias.

BACKGROUND: The validity of self-reported mammography uptake is often questioned. We assessed the related selection and reporting biases among women aged 50-69 years in the Belgian Health Interview Survey (BHIS) using reimbursement data for mammography stemming from the Belgian Compulsory Health Insurance organizations (BCHI). METHODS: Individual BHIS 2013 data (n = 1040) were linked to BCHI data 2010-13 (BHIS-BCHI sample). Being reimbursed for mammography within the last 2-years was used as the gold standard. Selection bias was assessed by comparing BHIS estimates reimbursement rates in BHIS-BCHI with similar estimates from the Echantillon Permanent/Permanente Steekproef (EPS), a random sample of BCHI data, while reporting bias was investigated by comparing self-reported versus reimbursement information in the BHIS-BCHI. Reporting bias was further explored through measures of agreement and logistic regression. RESULTS: Mammography uptake rates based on self-reported information and reimbursement from the BHIS-BCHI were 75.5% and 69.8%, respectively. In the EPS, it was 64.1%. The validity is significantly affected by both selection bias {relative size = 8.93% [95% confidence interval (CI): 3.21-14.64]} and reporting bias [relative size = 8.22% (95% CI: 0.76-15.68)]. Sensitivity was excellent (93.7%), while the specificity was fair (66.4%). The agreement was moderate (kappa = 0.63). Women born in non-EU countries (OR = 2.81, 95% CI: 1.54-5.13), with high household income (OR = 1.27, 95% CI: 1.02-1.60) and those reporting poor perceived health (OR = 1.41, 95% CI: 1.14-1.73) were more likely to inaccurately report their mammography uptake. CONCLUSIONS: The validity of self-reported mammography uptake in women aged 50-69 years is affected by both selection and reporting bias. Both administrative and survey data are complementary when assessing mammography uptake.

Is the European Health Interview Survey online yet? Response and net sample composition of a web-based data collection.

BACKGROUND: The European Health Interview Survey (EHIS) provides cross-national data on health status, health care and health determinants. So far, 10 of the 30 member states (MS) opted for web-based questionnaires within mixed-mode designs but none used it as the sole mode. In the context of future EHIS, the response rate and net sample composition of a web-only approach was tested. METHODS: A Belgian study with a target sample size of 1000 (age: 16-85) was organized using the EHIS wave 3 model questionnaire. The sample was selected according to a multistage, clustered sampling procedure with geographical stratification. Field substitution was applied; non-participating households were replaced by similar households regarding statistical sector, sex and age. There was one reminder letter and a €10 conditional incentive. RESULTS: Considering all substitutions, a 16% response rate was obtained after sending one reminder. Elderly, Brussels Capital inhabitants, people living without a partner and those with a non-Belgian nationality were less responding. By design, there were no differences between the initial and final net sample regarding substitution characteristics. Nevertheless, people living without a partner, non-Belgians and lower educated people remain underrepresented. CONCLUSION: There was a low response rate, particularly for some population groups. The response rate was lower than those of MS using mixed-mode designs including web, especially these comprising interviewer-based approaches. Despite the long and complex questionnaire, there was a low break off rate. So far, web-only data collection is not an acceptable strategy for population-based health surveys but efforts to increase the response should be further explored.

Mixing mixed-mode designs in a national health interview survey: a pilot study to assess the impact on the self-administered questionnaire non-response.

BACKGROUND: Many population health surveys consist of a mixed-mode design that includes a face-to-face (F2F) interview followed by a paper-and-pencil (P&P) self-administered questionnaire (SAQ) for the sensitive topics. In order to alleviate the burden of a supplementary P&P questioning after the interview, a mixed-mode SAQ design including a web and P&P option was tested for the Belgian health interview survey. METHODS: A pilot study (n = 266, age 15+) was organized using a mixed-mode SAQ design following the F2F interview. Respondents were invited to complete a web SAQ either immediately after the interview or at a later time. The P&P option was offered in case respondents refused or had previously declared having no computer access, no internet connection or no recent usage of computers. The unit response rate for the web SAQ and the overall unit response rate for the SAQ independent of the mode were evaluated. A logistic regression analysis was conducted to explore the association of socio-demographic characteristics and interviewer effects with the completed SAQ mode. Furthermore, a logistic regression analysis assessed the differential user-friendliness of the SAQ modes. Finally, a logistic multilevel model was used to evaluate the item non-response in the two SAQ modes while controlling for respondents' characteristics. RESULTS: Of the eligible F2F respondents in this study, 76% (107/140) agreed to complete the web SAQ. Yet among those, only 78.5% (84/107) actually did. At the end, the overall (web and P&P) SAQ unit response rate reached 73.5%. In this study older people were less likely to complete the web SAQ. Indications for an interviewer effect were observed as regard the number of web respondents, P&P respondents and respondents who refused to complete the SAQ. The web SAQ scored better in terms of user-friendliness and presented higher item response than the P&P SAQ. CONCLUSIONS: The web SAQ performed better regarding user-friendliness and item response than the P&P SAQ but the overall SAQ unit response rate was low. Therefore, future research is recommended to further assess which type of SAQ design implemented after a F2F interview is the most beneficial to obtain high unit and item response rates.

Contribution of chronic conditions to smoking differences in life expectancy with and without disability in Belgium.

Background: Smoking is the leading cause of premature mortality and morbidity. This study aimed at assessing the impact of smoking on life expectancy (LE) and LE with (LED) and without disability (DFLE). We further estimated the contribution of disability and mortality and their causes to differences in LED and DFLE by smoking. Methods: Data on disability, chronic conditions, and smoking from 17 148 participants of the 1997, 2001, 2004 Belgian Health Interview Surveys were used to estimate causes of disability using the attribution method. A 10-year mortality follow-up of survey participants was used. The Sullivan method was applied to estimate LED and DFLE. The contribution of disability and mortality and of causes of disability and death to smoking differences in LED and DFLE was assessed using decomposition methods. Results: Never smokers live longer than daily smokers. DFLE advantage at age 15 of +8.5/+4.3 years (y) in men/women never compared with daily smokers was the result of lower mortality (+6.2y/+3y) and lower disability (2.3y/1.3y). The extra 0.3y/1.6y LED in never smokers was due to lower mortality (+2.6y/+2.9y) and lower disability (-2.3y/-1.3y). Lower mortality from lung/larynx/trachea cancer, chronic respiratory, and ischaemic heart diseases was the main contributor to higher LED and DFLE in never smokers. Lower disability from musculoskeletal conditions in men and chronic respiratory diseases in women increased LED and DFLE in never smokers. Conclusions: Mortality and disability advantage among never smokers contributed to longer DFLE, while mortality advantage contributed to their longer LED.

Additional weighting for education affects estimates from a National Health Interview Survey.

Background: National Health Interview Surveys are used to produce country-wide results for a substantial number of health indicators. However, if some educational groups are underrepresented in the sample, estimates may be biased. This study investigated the impact of the use of post-stratification weights that adjust for the population distribution by education on estimates from the Belgian Health Interview Survey 2013. Methods: For 25 health-related indicators that match the European Core Health Indicator shortlist, estimates were computed using two different sets of post-stratification weights: one based on age group, gender and province only and the other one including also education. The Census 2011 was used as auxiliary data source. Statistical differences between the two estimates were assessed with the Delta method. Results: If education is not included as post-stratification weighting factor, low educational groups (ISCED 0-2) represent 31.1% of the total study population aged 25 years and older. If education is taken into account this proportion rises to 40.3%. The use of post-stratification weights adjusting for the population distribution by education has an impact on several survey estimates. The most pronounced effect is an increase in the estimated proportion of people with diabetes (+0.73%; 95% CI 0.19-1.27; relative increase +11.6%), asthma (+0.52%; 95% CI, 0.06-0.98; relative increase +12.4%) and difficulties to cover their health expenses (+2.31%; 95% CI, 1.52-3.10; relative increase +9.4%). Conclusions: Including education in the calculation of post-stratification weights reduces bias due to educational differences in survey participation. Auxiliary information used to calculate post-stratification weights for national health surveys should include education.

Using mortality follow-up of surveys to estimate social inequalities in healthy life years.

BACKGROUND: The estimation of healthy life years (HLY) by socio-economic status (SES) requires two types of data: the prevalence of activity limitation by SES generally extracted from surveys and mortality rates by SES generally derived from a linkage between the SES information in population databases (census, register) and mortality records. In some situations, no population-wide databases are available to produce mortality rates by SES, and therefore some alternatives must be explored. This paper assesses the validity of calculating HLY by SES using mortality rates derived from a linkage between surveys and mortality records. METHODS: TWO SURVEYS WERE CHOSEN TO EXPLORE THE VALIDITY OF THE PROPOSED APPROACH: The Belgian Health Interview Survey (HIS) and the Belgian Survey on Income and Living Conditions (SILC). The mortality follow-up of these surveys were used to calculate HLY by educational level at age 25. These HLY were compared with HLY estimates calculated using the mortality follow-up of the 2001 census. The validity of this approach was evaluated against two criteria. First, the HLY calculated using the census and those calculated using the surveys must not be significantly different. Second, survey-based HLY must show significant social inequalities since such inequalities have been consistently reported with census-based HLY. RESULTS: Both criteria were met. First, for each educational category, no statistically significant difference was found when comparing census-based and survey-based HLY estimates. For instance, men in the lowest educational category have shown a HLY of 34 years according to the HIS, and while this figure was 35.5 years according to the census, this difference was not statistically significant. Second, the survey-based HLY have shown a significant social gradient. For instance, men in the highest educational category are expected to live 9.5 more HLY than their counterparts in the lowest educational category based on the HIS estimates, compared with 7.3 HLY based on the census estimates. CONCLUSIONS: This article suggests that using the mortality follow-up of a nationally representative cross-sectional survey is a valid approach to monitor social inequalities in HLY in the absence of population-wide data.

The effect of smoking on the duration of life with and without disability, Belgium 1997-2011.

BACKGROUND: Smoking is the single most important health threat yet there is no consistency as to whether non-smokers experience a compression of years lived with disability compared to (ex-)smokers. The objectives of the manuscript are (1) to assess the effect of smoking on the average years lived without disability (Disability Free Life Expectancy (DFLE)) and with disability (Disability Life Expectancy (DLE)) and (2) to estimate the extent to which these effects are due to better survival or reduced disability in never smokers. METHODS: Data on disability and mortality were provided by the Belgian Health Interview Survey 1997 and 2001 and a 10 years mortality follow-up of the survey participants. Disability was defined as difficulties in activities of daily living (ADL), in mobility, in continence or in sensory (vision, hearing) functions. Poisson and multinomial logistic regression models were fitted to estimate the probabilities of death and the prevalence of disability by age, gender and smoking status adjusted for socioeconomic position. The Sullivan method was used to estimate DFLE and DLE at age 30. The contribution of mortality and of disability to smoking related differences in DFLE and DLE was assessed using decomposition methods. RESULTS: Compared to never smokers, ex-smokers have a shorter life expectancy (LE) and DFLE but the number of years lived with disability is somewhat larger. For both sexes, the higher disability prevalence is the main contributing factor to the difference in DFLE and DLE. Smokers have a shorter LE, DFLE and DLE compared to never smokers. Both higher mortality and higher disability prevalence contribute to the difference in DFLE, but mortality is more important among males. Although both male and female smokers experience higher disability prevalence, their higher mortality outweighs their disability disadvantage resulting in a shorter DLE. CONCLUSION: Smoking kills and shortens both life without and life with disability. Smoking related disability can however not be ignored, given its contribution to the excess years with disability especially in younger age groups.

Rising socioeconomic disparities in childhood overweight and obesity in Belgium.

BACKGROUND: Childhood overweight, especially obesity, significantly impacts children's health and poses an increased risk of adult-onset diseases. This study aims to analyse the evolution of childhood overweight and obesity in Belgium from 1997 to 2018 and assess its variation across parental socioeconomic status (SES). METHODS: The Health Interview Survey, a cross-sectional survey representative of the Belgian population, has been conducted since 1997, with the latest survey conducted in 2018. This study focuses on children aged 2-17 years. Body Mass Index (BMI, kg/m²) was derived from self-reported data, supplemented with proxy reports for children under 15 years old. Overweight and obesity were classified using age/sex-specific cut-off points. Highest parental educational level served as the indicator of SES. In addition to reporting the overall prevalence and the 95% confidence interval (95%CI) of childhood overweight and obesity by year, this study examines the absolute difference in prevalence between SES groups (low minus high) and calculates the Odds Ratio (OR, adjusted for age and sex) to evaluate the relative difference. RESULTS: The overall prevalence of childhood overweight rose from 13.6% (95%CI = 11.2-16.1%) in 1997 to 18.9% (95%CI = 16.3-21.5%) in 2018; while it remained stable for obesity, fluctuating between 5.4% and 6.3% over the same period. This increase was more pronounced among children with low SES compared to those with high SES. Consequently, the absolute difference between children with low and high SES increased over time from 8.0% points (pp) in 1997 to 14.9 pp in 2018 for overweight, and from 3.1 pp to 6.8 pp for obesity. In terms of relative inequalities, overall, children with low SES exhibited significantly higher odds of overweight and of obesity than those with high SES (OR varying between 2 à 3 for overweight and between 2 and 4 for obesity). CONCLUSIONS: The escalating disparities over time highlight SES as a significant risk factor for childhood overweight and obesity. Addressing these inequalities requires interventions such as providing healthy meals and increasing sports opportunities at school. Additionally, it is recommended to regulate fast food outlets near schools and limit unhealthy food marketing, particularly because children with low SES are more exposed to such influences.

Using multiple measures of inequalities to study the time trends in social inequalities in smoking.

BACKGROUND: The time trends in social inequalities in smoking have been examined in a number of international publications; however, these studies have rarely used multiple measures of health inequalities simultaneously. Also the analytical approach used often did not account, as recommended, for the changes in the relative distribution of social groups and the changes in the absolute level of the health outcome within social groups. METHODS: Data from four successive waves of the Belgian Health Interview Survey (1997, 2001, 2004, 2008) were used to study the time trends in educational inequalities in daily smoking for those aged between 15 and 74 years. We estimated two measures of relative inequalities: the OR and the relative index of inequality; and two measures of absolute inequalities: the population attributable fraction and the slope index of inequality. Three of these measures (relative index of inequality, population attributable fraction, slope index of inequality) account for the change in the relative size of the social groups over time. RESULTS: The four measures of inequality were consistent in showing significant inequalities among educational groups. The time trends, however, were less consistent. Measures of trends in relative inequalities witnessed a small linear increase. However, no substantial over time change was observed with the measures of absolute inequalities. CONCLUSION: The time trends in social inequalities in smoking varied according to the measure of inequality used. This study confirms the importance of using multiple measures of inequalities to understand and monitor social inequalities in smoking.