Alison Moody

Scoring the Icecap-a Capability Instrument. Estimation of a UK General Population Tariff†

This paper reports the results of a best–worst scaling (BWS) study to value the Investigating Choice Experiments Capability Measure for Adults (ICECAP-A), a new capability measure among adults, in a UK setting. A main effects plan plus its foldover was used to estimate weights for each of the four levels of all five attributes. The BWS study was administered to 413 randomly sampled individuals, together with sociodemographic and other questions. Scale-adjusted latent class analyses identified two preference and two (variance) scale classes. Ability to characterize preference and scale heterogeneity was limited, but data quality was good, and the final model exhibited a high pseudo-r-squared. After adjusting for heterogeneity, a population tariff was estimated. This showed that ‘attachment’ and ‘stability’ each account for around 22% of the space, and ‘autonomy’, ‘achievement’ and ‘enjoyment’ account for around 18% each. Across all attributes, greater value was placed on the difference between the lowest levels of capability than between the highest. This tariff will enable ICECAP-A to be used in economic evaluation both within the field of health and across public policy generally.

An investigation of the construct validity of the ICECAP-A capability measure

PurposeTo investigate the construct validity of the ICECAP-A capability wellbeing measure.MethodsA face-to-face interview-administered survey was conducted with 418 members of the UK general population, randomly sampled from the Postcode Address File. Pre-specified hypotheses were developed about the expected associations between individuals’ ICECAP-A responses and their socio-economic circumstances, health and freedom. The hypotheses were investigated using statistical tests of association.ResultsThe ICECAP-A responses and scores reflected differences across different health and socioeconomic groups as anticipated, but did not distinguish individuals by the level of local deprivation. Mean ICECAP-A scores reflected individuals’ perceived freedom slightly more closely than did measures of health and happiness.ConclusionThis study suggests that the ICECAP-A measure can identify expected differences in capability wellbeing in a general population sample. Further work could establish whether self-reported capabilities exhibit desirable validity and acceptability in sub-groups of the population such as patients, social care recipients and informal carers.

Social inequalities in prevalence of diagnosed and undiagnosed diabetes and impaired glucose regulation in participants in the Health Surveys for England series

Objectives To ascertain the extent of socioeconomic and health condition inequalities in people with diagnosed and undiagnosed diabetes and impaired glucose regulation (IGR) in random samples of the general population in England, as earlier diagnosis of diabetes and treatment of people with IGR can reduce adverse sequelae of diabetes. Various screening instruments were compared to identify IGR, in addition to undiagnosed diabetes. Design 5, annual cross-sectional health examination surveys; data adjusted for complex survey design. Setting Random selection of private homes across England, new sample annually 2009–2013. Participants 5, nationally representative random samples of the general, free-living population: ≥1 adult interviewed in 24 254 of 36 889 eligible addresses selected. 18 399 adults had a valid glycated haemoglobin (HbA1c) measurement and answered the diabetes questions. Main outcome measures Diagnosed diabetes, undiagnosed diabetes (HbA1c ≥48 mmol/mol), IGR (HbA1c 42–47 mmol/mol). Results Overall, 11% of the population had IGR, 2% undiagnosed and 6% diagnosed diabetes. Age-standardised prevalence was highest among Asian (19% (95% CI 16% to 23%), 3% (2% to 5%) and 12% (9% to 16%) respectively) and black participants (17% (13% to 21%), 2% (1% to 4%) and 14% (9% to 20%) respectively). These were also higher among people with lower income, less education, lower occupational class and greater deprivation. Education (OR 1.49 (95% CI 1.27 to 1.74) for no qualifications vs degree or higher) and income (1.35 (1.12 to 1.62) for lowest vs highest income quintile) remained significantly associated with IGR or undiagnosed diabetes on multivariate regression. The greatest odds of IGR or undiagnosed diabetes were with increasing age over 34 years (eg, OR 18.69 (11.53 to 30.28) aged 65–74 vs 16–24). Other significant associations were ethnic group (Asian (3.91 (3.02 to 5.05)), African-American (2.34 (1.62 to 3.38)) or ‘other’ (2.04 (1.07 to 3.88)) vs Caucasian); sex (OR 1.32(1.19 to 1.46) for men vs women); body mass index (3.54 (2.52 to 4.96) for morbidly obese vs not overweight); and waist circumference (2.00 (1.67 to 2.38) for very high vs low). Conclusions Social inequalities in hyperglycaemia exist, additional to well-known demographic and anthropometric risk factors for diabetes and IGR.

Estimating population prevalence of potential airflow obstruction using different spirometric criteria: a pooled cross-sectional analysis of persons aged 40–95 years in England and Wales

Objectives Consistent estimation of the burden of chronic obstructive pulmonary disease (COPD) has been hindered by differences in methods, including different spirometric cut-offs for impaired lung function. The impact of different definitions on the prevalence of potential airflow obstruction, and its associations with key risk factors, is evaluated using cross-sectional data from two nationally representative population surveys. Design Pooled cross-sectional analysis of Wave 2 of the UK Household Longitudinal Survey and the Health Survey for England 2010, including 7879 participants, aged 40–95 years, who lived in England and Wales, without diagnosed asthma and with good-quality spirometry data. Potential airflow obstruction was defined using self-reported physician-diagnosed COPD; a fixed threshold (FT) forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio <0.7 and an age-specific, sex-specific, height-specific and ethnic-specific lower limit of normal (LLN). Standardised questions elicited self-reported information on demography, smoking history, ethnicity, occupation, respiratory symptoms and cardiovascular disease. Results Consistent across definitions, participants classed with obstructed airflow were more likely to be older, currently smoke, have higher pack-years of smoking and be engaged in routine occupations. The prevalence of airflow obstruction was 2.8% (95% CI 2.3% to 3.2%), 22.2% (21.2% to 23.2%) and 13.1% (12.2% to 13.9%) according to diagnosed COPD, FT and LLN, respectively. The gap in prevalence between FT and LLN increased in older age groups. Sex differences in the risk of obstruction, after adjustment for key risk factors, was sensitive to the choice of spirometric cut-off, being significantly higher in men when using FT, compared with no significant difference using LLN. Conclusions Applying FT or LLN spirometric cut-offs gives a different picture of the size and distribution of the disease burden. Longitudinal studies examining differences in unscheduled hospital admissions and risk of death between FT and LLN may inform the choice as to the best way to include spirometry in assessments of airflow obstruction.

Using longitudinal data from the Health Survey for England to resolve discrepancies in thresholds for haemoglobin in older adults

Anaemia increases with age and is common among older people. Due to its relationship with morbidity and mortality, accurate diagnosis is important. Thresholds defining the diagnosis of anaemia have been the subject of considerable scientific debate, with both higher and lower cut‐offs proposed. High haemoglobin is also a health risk in some but not all studies. Using nationally representative data of 5,329 adults aged 65 + years (Health Survey for England 1998, 2005, 2006), linked to administrative mortality data, this paper describes the relationship between haemoglobin levels and mortality, adjusted for age and other confounders. Among men, a reverse J shaped relationship was observed: relative to the modal group (140–149 g/l), those with ‘mild anaemia’ of 120–129 g/l haemoglobin had a 56% (95% confidence interval 24–96%) greater mortality hazard, and those with ‘severe anaemia’, haemoglobin <120 g/l, had an 87% (39–153%) greater hazard. At the other end of the range, those with haemoglobin ≥160 g/l had 32% (2–70%) greater mortality hazard. Haemoglobin levels in women showed a similar but smaller, non‐significant pattern: hazard ratio 1·32 (0·91–1·92) for severe anaemia (<110 g/l), and 1·30 (0·95–1·79) for high haemoglobin (≥150 g/l). This research supports the use of the World Health Organization thresholds (130 g/l for men, 120 g/l for women).

Impaired Glucose Metabolism among Those with and without Diagnosed Diabetes and Mortality: A Cohort Study Using Health Survey for England Data

Background The extent that controlled diabetes impacts upon mortality, compared with uncontrolled diabetes, and how pre-diabetes alters mortality risk remain issues requiring clarification. Methods We carried out a cohort study of 22,106 Health Survey for England participants with a HbA1C measurement linked with UK mortality records. We estimated hazard ratios (HRs) of all-cause, cancer and cardiovascular disease (CVD) mortality and 95% confidence intervals (CI) using Cox regression. Results Average follow-up time was seven years and there were 1,509 deaths within the sample. Compared with the non-diabetic and normoglycaemic group (HbA1C <5.7% [<39mmol/mol] and did not indicate diabetes), undiagnosed diabetes (HbA1C ≥6.5% [≥48mmol/mol] and did not indicate diabetes) inferred an increased risk of mortality for all-causes (HR 1.40, 1.09–1.80) and CVD (1.99, 1.35–2.94), as did uncontrolled diabetes (diagnosed diabetes and HbA1C ≥6.5% [≥48mmol/mol]) and diabetes with moderately raised HbA1C (diagnosed diabetes and HbA1C 5.7-<6.5% [39-<48mmol/mol]). Those with controlled diabetes (diagnosed diabetes and HbA<5.7% [<39mmol/mol]) had an increased HR in relation to mortality from CVD only. Pre-diabetes (those who did not indicate diagnosed diabetes and HbA1C 5.7-<6.5% [39-<48mmol/mol]) was not associated with increased mortality, and raised HbA1C did not appear to have a statistically significant impact upon cancer mortality. Adjustment for BMI and socioeconomic status had a limited impact upon our results. We also found women had a higher all-cause and CVD mortality risk compared with men. Conclusions We found higher rates of all-cause and CVD mortality among those with raised HbA1C, but not for those with pre-diabetes, compared with those without diabetes. This excess differed by sex and diabetes status. The large number of deaths from cancer and CVD globally suggests that controlling blood glucose levels and policies to prevent hyperglycaemia should be considered public health priorities.

Has the UK Healthy Start voucher scheme been associated with an increased fruit and vegetable intake among target families? Analysis of Health Survey for England data, 2001–2014

Background Healthy Start (HS) is a UK government programme, introduced in 2006, providing vouchers to pregnant women or families with children aged <4 who are in receipt of certain benefits. Vouchers can be exchanged for fruit and vegetables (F&V), milk or infant formula. We sought to identify any association between HS and F&V intake. Methods We analysed repeated cross-sectional data from the Health Survey for England. Study participants were classified into one of four groups: one HS-eligible group and three control groups, meeting only the income or demographic or no eligibility criterion. Outcome measures were mean F&V intake and the proportions of participants consuming ≥3 and ≥1 portion/day. Outcomes were compared across the four groups over four time periods: 2001–2003, 2004–2006, 2007–2009 and 2010–2014. Regression analyses examined whether F&V intake among HS-eligible participants had a significantly different rate of change from those in the control groups. Results The change in mean F&V consumption over time was similar in HS-eligible adults and children to that of the control groups. Likewise, the change in odds of consuming ≥3 or ≥1 portion of F&V/day over time was similar among HS-eligible participants and control groups. Conclusion This study found that during the period 2001–2003 to 2010–2014, F&V consumption among adults and children in households deemed eligible for HS changed similarly to that of other adults and children. Potential explanations include that vouchers may have been spent on milk or infant formula, or that vouchers helped protect F&V consumption in low-income households.

P59 Changes in the body mass index and waist circumference distribution of adults aged 25–64 years in England, Scotland, and the United States, 1998–2012

Background Body Mass Index (BMI) and waist circumference (WC) are anthropometric indicators strongly associated with diabetes, cardiovascular disease, cancer and mortality. Focusing on secular changes in the mean values of BMI and WC can mask differences at the lower- and upper-tails of the distribution. Our network of health examination survey researchers from the Americas and the UK quantified secular changes in the BMI and WC distributions in England, Scotland, and the United States (US). Methods Nationally-representative surveys of adults aged 25–64 y from similar time periods: Health Survey for England (1999–2012; n = 75,813); Scottish Health Survey (1998–2011; n = 33,010) and US National Health and Nutrition Examination Survey (1999–2012; n = 22,340). Comparisons across time for mean values of measured height, weight, BMI, and WC and prevalence of obesity (BMI ≥ 30 kg/m2) and abdominal obesity (WC ≥ 88 cm) were performed by age-standardising descriptive estimates by the direct-method to the 2000 US population. Quantile regression was used to evaluate whether BMI and WC values increased across survey years at pre-specified centiles of the distribution (5th, 50th, 95th). Models were adjusted for age, age-squared and survey year. Results Mean BMI values for men (women) at baseline were 27.1 kg/m2 (26.6 kg/m2) in England; 27.1 kg/m2 (26.8 kg/m2) in Scotland; and 27.8 kg/m2 (28.6 kg/m2) in the US. Obesity and abdominal obesity increased for both sexes in England and in Scotland. In the US, obesity increased only for men; abdominal obesity increased only for women. Mean BMI increased by 0.4 kg/m2 (0.7 kg/m2) for men (women) in England; 0.8 kg/m2 for both sexes in Scotland; and 1.0 kg/m2 for men in the US. BMI at the 5th centile was unchanged in England, but increased in Scotland and the US. Increases at the median and upper-tail occurred in each country: the increase at the 95th BMI percentile was 2.1 kg/m2 (1.3 kg/m2) for men (women) in England; 1.9 kg/m2 for both sexes in Scotland; and 2.0 kg/m2 (1.9 kg/m2) in the US (each P < 0.001). Mean WC increased by 2.1 cm (4.7 cm) for men (women) in England; 3.4 cm (6.5 cm) in Scotland; and 2.4 cm (3.8 cm) in the US. The increase at the 95th WC percentile was 6.3 cm (5.4 cm) for men (women) in England; 3.6 cm (8.4 cm) in Scotland; and 4.5 cm (18.3 cm) in the US (each P < 0.001). Ongoing analyses will incorporate data from Chile, Colombia, Mexico, and Brazil. Conclusion Secular increases in BMI and WC were fairly consistent by country for both sexes, with clear evidence of increases across the whole distribution in Scotland and the US.

PP60 Probable Airflow Obstruction in Adults: Data from the Health Survey for England 2010

Background In the UK, chronic obstructive pulmonary disease (COPD) causes approximately 25,000 deaths annually. Around three million people are estimated to have COPD, of whom fewer than one-third have been diagnosed. Using spirometry, fixed thresholds (FT) and lower limit of normal (LLN) criteria define airflow obstruction (AO) differently. FTs use cut-offs for lung function measurements regardless of age, sex, height and ethnicity; LLN criteria use cut-offs (e.g. 5th centile) based on normalised values for a healthy person of a given age, sex, height and ethnic group. Although FTs are widely used, LLN criteria are recommended in epidemiological studies as FTs overestimate AO in the elderly due to age-related changes in lung function. Methods The Health Survey for England 2010 focused on respiratory health and included spirometry (without bronchodilators) in a nationally representative random general population sample. For participants aged ≥45years without asthma (n = 1635), we estimated the prevalence of self-reported doctor-diagnosed COPD. Using the Global Lungs Initiative 2012 multi-ethnic reference equations, prevalence rates of probable AO were estimated using four definitions: FT: FEV1/FVC<0.70 FT + : FEV1/FVC<0.70 and FEV1<80% predicted LLN: FEV1/FVC LLN + : FEV1/FVC and FEV1 These definitions are overlapping. We estimated the prevalence of COPD within each probable AO group. Potential risk factors for COPD or for probable AO were analysed using logistic regression (five separate outcomes). Results 5% of participants reported doctor-diagnosed COPD. The prevalence of probable AO was 24% (FT), 12% (FT +), 14% (LLN) and 7% (LLN +). 17% of participants in the FT + group reported COPD compared with 24% of participants in the LLN + group. Pack-years smoked and respiratory symptoms significantly increased the odds of COPD and of AO after adjustments for age, sex, socioeconomic status and exposure to passive smoking. Compared with never regular smokers, those with 50 + pack-years had 5.8 (95% CI 2.6, 13.0) times higher odds of reporting diagnosed COPD, and 5.5 (3.0, 10.3) and 6.8 (3.2, 14.8) times higher odds of probable AO by FT + and LLN + criteria, respectively. Participants with respiratory symptoms had 2.5 (1.1, 5.7), 2.0 (1.0, 4.0) and 2.8 (1.3, 5.7) times higher odds of COPD/AO respectively than those without respiratory symptoms. Participants meeting LLN probable AO criteria had higher odds of diagnosed COPD: FT 2.0 (1.2, 3.5); FT + 40 (2.2, 7.1); LLN 4.2 (2.4, 7.3); LLN + 5.7 (3.0, 10.8). Conclusion As post-bronchodilator spirometry was not used in HSE 2010, our results may overestimate the true prevalence of AO, but this large population survey confirms that substantial underdiagnosis of COPD remains likely. LLN criteria appear to identify fewer, more severely affected individuals than FT criteria.

OP04 Airway Obstruction and All-Cause and Respiratory Mortality: Exploring the Relationship between three Definitions of Obstruction, Smoking using Healths Survey for England and Scottish Health Survey Data

Background Debate continues about the predictive value of different spirometry based definitions of chronic obstructive pulmonary disease (COPD). We explored the hazard of death for three overlapping definitions, and any significant interactions with smoking. Methods Data from the Health Survey for England (years 1995–1997, 2001) and Scottish Health Survey (1995, 1998, and 2003) were used. 30001 adults aged 45+ were interviewed, had spirometry data, and linked mortality records (HSE extracted in 2011; SHeS in 2008). Cox regression was used to estimate the hazard ratios of those with COPD/airflow obstruction, compared with those without, adjusted for age, socio-economic position, smoking, drinking, body mass index (BMI), and longstanding-illness. Sex-specific models, for all-cause and respiratory mortality, used three definitions: fixed threshold (FT): FEV1/FVC < 0.70 and FEV1 < 80% predicted; lower limit of normal (LLN): FEV1/FVC1; self-reported COPD as a longstanding-illness (COPD). Results For men meeting FT criteria the hazard ratio (HR) for all-cause mortality was 1.49 (95% CI 1.37, 1.62), compared with those not meeting the criteria. Despite capturing a smaller group, the HR for LLN was not significantly different: 1.60 (1.44, 1.78), nor was the HR for those reporting COPD 1.73 (1.45, 2.05). Similar, overlapping ratios were found for women: FT 1.52 (1.37, 1.68); LLN 1.62 (1.42, 1.85) and COPD 1.76 (1.42, 2.18). The relationship between COPD/obstructed airflow and mortality was stronger for respiratory mortality, with greater differentiation between measures. Among men, FT HR 2.69 (2.16, 3.36) just overlapped with LLN 4.20 (3.30, 5.35), but was lower than reported COPD 5.19 (3.79, 7.10). Among women, the figures were: FT 3.46 (2.68, 4.47), LLN 4.24 (3.17, 5.66), COPD 6.36 (4.31, 9.37). Smoking was a significant risk factor for mortality in all models, independently of airway obstruction, but results showed a significant interaction between cigarette pack-years and COPD. Among adults without COPD, the HR gradually increased to 1.7 (all-cause mortality) for those with 50+ pack-years, relative to never smokers and around 2 for respiratory deaths. Among adults reporting COPD, the HR for pack-years ≥1 was around 3 for all-cause and >6 for respiratory deaths. Conclusion Participants mentioning COPD as a longstanding illness had the highest respiratory mortality. The HR for those meeting LLN criteria was higher, but not significantly so, than using FT. Any history of smoking increased mortality dramatically among those reporting COPD, compared with a more graded increase of risk by number of pack-years for those not reporting COPD.