Liquid-liquid equilibria of binary mixtures of a lipidic ionic liquid with hydrocarbons.

Although structurally diverse, many ionic liquids (ILs) are polar in nature due to the strong coulombic forces inherent in ionic compounds. However, the overall polarity of the IL can be tuned by incorporating significant nonpolar content into one or more of the constituent ions. In this work, the binary liquid-liquid equilibria of one such IL, 1-methyl-3-(Z-octadec-9-enyl)imidazolium bistriflimide, with several hydrocarbons (n-hexane, n-octane, n-decane, cyclohexane, methylcyclohexane, 1-octene) is measured over the temperature range 0-70 °C at ambient pressure using a combination of cloud point and gravimetric techniques. The phase behavior of the systems are similar in that they exhibit two phases: one that is 60-90 mole% hydrocarbon and a second phase that is nearly pure hydrocarbon. Each phase exhibits a weak dependence of composition on temperature (steep curve) above ∼10 °C, likely due to swelling and restructuring of the nonpolar nano-domains of the IL being limited by energetically unfavorable restructuring in the polar nano-domains. The solubility of the n-alkanes decreases with increasing size (molar volume), a trend that continues for the cyclic alkanes, for which upper critical solution temperatures are observed below 70 °C. 1-Octene is found to be more soluble than n-octane, attributable to a combination of its lower molar volume and slightly higher polarity. The COSMO-RS model is used to predict the T-x'-x'' diagrams and gives good qualitative agreement of the observed trends. This work presents the highest known solubility of n-alkanes in an IL to date and tuning the structure of the ionic liquid to maximize the size/shape trends observed may provide the basis for enhanced separations of nonpolar species.

A decade of research using the CASP scale: key findings and future directions.

Since the publication of A Measure of Quality of Life in Early Old Age: The Theory, Development and Properties of a Needs Satisfaction Model (CASP-19) just over 10 years ago, the scale has gone on to be used in a wide variety of studies in over 20 countries across the world and the original paper has become the most highly cited paper for Aging and Mental Health. Therefore it was felt that it was a good time to look back and reflect on the developments in the use of the scale as well as to look forward to what new research is being done and could be done with the measure. To this end we are extremely grateful for the editors for allowing us to bring together a collection of papers that represent cutting edge research using the CASP scale. These papers cover a wide variety of issues, from working conditions to religiosity, from a range of countries, covering Western and Eastern Europe as well as Africa. Each makes an important individual contribution to our understanding of the factors that influence quality of life in later life as well as pointing to the limitations of the measure and future work that can be done in this area.

Housing and respiratory health at older ages.

BACKGROUND: A large proportion of the population of England live in substandard housing. Previous research has suggested that poor-quality housing, particularly in terms of cold temperatures, mould, and damp, poses a health risk, particularly for older people. The present study aimed to examine the association between housing conditions and objectively measured respiratory health in a large general population sample of older people in England. DATA AND METHODS: Data on housing conditions, respiratory health and relevant covariates were obtained from the second wave of the English Longitudinal Study of Ageing. Multivariate regression methods were used to test the association between contemporary housing conditions and respiratory health while accounting for the potential effect of other factors; including social class, previous life-course housing conditions and childhood respiratory health. RESULTS: Older people who were in fuel poverty or who did not live in a home they owned had significantly worse respiratory health as measured by peak expiratory flow rates. After accounting for covariates, these factors had no effect on any other measures of respiratory health. Self-reported housing problems were not consistently associated with respiratory health. CONCLUSIONS: The housing conditions of older people in England, particularly those associated with fuel poverty and living in rented accommodation, may be harmful to some aspects of respiratory health. This has implications for upcoming UK government housing and energy policy decisions.

Fuel poverty and the health of older people: the role of local climate.

BACKGROUND: Fuel poverty is a risk factor for ill-health, particularly among older people. We hypothesized that both the risk of fuel poverty and the strength of its detrimental effects on health would be increased in areas of colder and wetter climate. METHODS: Individual data on respiratory health, hypertension, depressive symptoms and self-rated health were derived from the 2008/09 wave of the English Longitudinal Study of Ageing. Climate data for 89 English counties and unitary authorities were obtained from the UK Met Office. Multilevel regression models (n = 7160) were used to test (i) the association between local climate and fuel poverty risk, and (ii) the association between local climate and the effect of fuel poverty on health (adjusted for age, gender, height, smoking status and household income). RESULTS: Individual risk of fuel poverty varied across counties. However, this variation was not explained by differences in climate. Fuel poverty was significantly related to worse health for two of the outcomes (respiratory health and depressive symptoms). However, there was no significant effect of climate on fuel poverty's association with these outcomes. CONCLUSIONS: Although there is regional variation in England in both the risk of fuel poverty and its effects on health, this variation is not explained by differences in rainfall and winter temperatures.

Dietary assessment in early old age: experience from the Boyd Orr cohort.

BACKGROUND: The assessment of the impact of data quality issues, such as omitting to answer questions on a food frequency questionnaire (FFQ), is important in all study populations, including those in early old age. Assumptions about the limited nature of diets of older participants may influence the treatment and interpretation of their dietary data. SUBJECTS/METHODS: The Boyd Orr cohort is a long-term study based on 4999 UK men and women whose families took part in a survey of diet and health during 1937-1939. In 1997-1998, all 3182 traced, surviving study members, then aged 60 years and over, were sent a health and lifestyle questionnaire, including a 113-item FFQ, primarily to examine relationships between childhood and adult fruit, vegetable and antioxidant intakes. In-depth interviews were conducted with a purposively sampled subset of 31 respondents. RESULTS: Of the 1475 subjects who returned the questionnaire, 11% (n=161) had missing data on their FFQ. Those who omitted answers to more than 10 questions (n=127; 8.6%) were more likely to be aged over 70, to be female, but no more likely to report being overweight than those with 10 or fewer missing answers. Follow-up by telephone or post to reassess missing FFQ data was successful for 102 of the subjects with more than 10 omitted answers. Mean intakes of energy, fruit and vegetables, and selected nutrients were significantly increased after reassessment. The use of 'cross-check' questions to weigh fruit and vegetable intake (n=1383) showed potentially systematic errors in the reporting of these foods, vitamin C and carotene. Analysis of interview data among a subset of participants partially challenged stereotypical views of the diets of older people with, for example, increased freedom in food choice associated with life transitions. CONCLUSIONS: Food frequency questionnaires for those in early old age, as for others, need to meet competing demands of being comprehensive for those with varied diets, while not being so onerous that they deter completion. Reviewing questionnaires with participants remains important in this group, as omitting to answer questions on the FFQ does not necessarily equate to non-consumption. Qualitative interviews may aid in the interpretation of the quantitative data obtained.

Mental health and resilience at older ages: bouncing back after adversity in the British Household Panel Survey.

BACKGROUND: Resilience is having good outcomes despite adversity and risk and could be described in terms of preserving the same level of the outcome or rebounding back to that level after an initial set back. Using the latter definition, resilience as "bouncing back", this paper aims (1) to identify those members of a panel survey who demonstrated resilience, and (2) to identify the characteristics of the resilient individuals and the predictors of their resilience. METHODS: The study subjects were the 3581 participants in the British Household Panel Survey, selected from waves 1-14, who satisfied three requirements: exposure to an adversity; availability of consecutive General Health Questionnaire (GHQ)-12 scores; aged 50 or more years. The primary outcome variable was resilience, operationalised as a GHQ-12 score that increased after exposure to adversity and returned to its pre-exposure level in the next (after 1 year) wave of the survey. The adversities were: functional limitation; bereavement or marital separation; poverty. RESULTS: The prevalence of resilience, as defined, was 14.5%. After adjusting for regression to the mean, the GHQ-12 score of the resilient dropped by a mean of 3.6 points in the post-adversity period. Women predominated among the resilient, with this gender difference stronger among older women than younger women. The resilient were more likely to have high social support than the non-resilient, but otherwise were not different socioeconomically. High social support pre-adversity and during adversity increased the likelihood of resilience by 40-60% compared with those with low social support. CONCLUSIONS: Resilience is relatively rare and favours older women. It is fostered by high levels of social support existing before exposure to adversity.

The claim for patient choice and equity.

Recently, commentators close to and within the UK government have claimed that patient choice can increase equity in the context of the National Health Service. This article critically examines the basis for this claim through analysis of recent speeches and publications authored by secretaries of state for health and their policy advisers. It is concluded that this claim has not developed prospectively from an analysis of the causes of healthcare inequity, or even with a consistent normative definition of equity. The limited justification that is "framed in causal explanations" of inequity has suffered from an apparent disregard of the available evidence.

The development of life course epidemiology.

The present paper reviews the development of life course epidemiology since its origins during the 1990s from biological programming, birth cohort research and the study of health inequalities. Methods of studying the life course are examined, including birth cohort studies, linked register datasets and epidemiological archaeology. Three models of life course epidemiology are described: critical periods, accumulation, and pathways. Their conceptual and empirical differentiation can be difficult, but it is argued that accumulation is the underlying social process driving life course trajectories, while the critical period and pathway models are distinguished by their concern with specific types of aetiological process. Among the advantages of the accumulation model are predictive power, aetiological insights, contributions to health inequality debates and social policy implications. It is emphasised that the life course approach is not opposed to, or an alternative to, a concern with cross-sectional and current effects; major social disruption can have a large and immediate impact on health. Other limitations of the life course approach include a spectrum of impact (life course effects can be strong in relation to physiology, but often are weaker in relation to behaviour and psychological reactions to everyday life) and, more speculatively, the possibility that life course effects are diluted in the older age groups where morbidity and mortality are highest. Three issues for the future of life course epidemiology are identified. Many life course data are collected retrospectively. We need to know which items of information are recalled with what degree of accuracy over how many decades; and what methods of collecting these retrospective data maximise accuracy and duration. Second, the two partners in life course research need to take more seriously each other's disciplines. Social scientists need to be more critical of such measures as self-assessed health, which lacks an aetiology and hence biological plausibility. Natural scientists need to be more critical of such concepts as socio-economic status, which lacks social plausibility because it fails to distinguish between social location and social prestige. Finally, European comparative studies can play an important part in the future development of life course epidemiology if they build on the emerging infrastructure of European comparative research.

Childhood IQ in relation to obesity and weight gain in adult life: the National Child Development (1958) Study.

OBJECTIVE: To examine the relation of childhood intelligence (IQ) test results with obesity in middle age and weight gain across the life course. METHODS: We analysed data from the National Child Development (1958) Study, a prospective cohort study of 17 414 births to parents residing in Great Britain in the late 1950s. Childhood IQ was measured at age 11 years and body mass index (BMI), an indicator of adiposity, was assessed at 16, 23, 33 and 42 years of age. Logistic regression (in which BMI was categorised into obese and non-obese) and structural equation growth curve models (in which BMI was retained as a continuous variable) were used to estimate the relation between childhood IQ and adult obesity, and childhood IQ and weight gain, respectively. RESULTS: In unadjusted analyses, lower childhood IQ scores were associated with an increased prevalence of adult obesity at age 42 years. This relation was somewhat stronger in women (OR(per SD decrease in IQ score) [95% CI]: 1.38 [1.26, 1.50]) than men (1.26 [1.15, 1.38]). This association remains statistically significant after adjusting for childhood characteristics, including socio-economic factors, but was heavily attenuated following control for adult characteristics, particularly education (women: 1.11 [0.99, 1.25]; men: 1.10 [0.98, 1.23]). When weight gain between age 16 and 42 years was the outcome of interest, structural equation modelling revealed that education and dietary characteristics in adult life mediated the association with childhood IQ. CONCLUSIONS: A lower IQ score in childhood is associated with obesity and weight gain in adulthood. In the present study, this relation appears to be largely mediated via educational attainment and the adoption of healthy diets in later life.

Person, place or time? The effect of individual circumstances, area and changes over time on mortality in men, 1995-2001.

This article uses the ONS Longitudinal Study to explore, for a cohort of adult males who were aged 26 or over in 1971, the relative influence on mortality in 1995-2001 of their place of residence and individual socioeconomic circumstances, at three censuses over a 20-year period. Factors examined in this analysis include social class, neighbourhoo deprivation (at ward level), unemployment, residence in the South East region in 1971 or 1981 housing tenure, and change in social class and housing tenure between 1971 and 1991. The variation in mortality attributable to the local authority district of residence in 1991 was also investigated.

Selecting a healthy diet score: lessons from a study of diet and health in early old age (the Boyd Orr cohort).

OBJECTIVES: To describe the selection and modification of an appropriate diet score to assess diet quality in early old age. DESIGN AND SETTING: Cross-sectional analyses of the Boyd Orr cohort - a long-term follow-up of men and women whose families took part in a survey of diet and health in pre-war Britain. Dietary data were obtained from a 113-item food-frequency questionnaire. A nine-item Healthy Diet Indicator (HDI) developed by Huijbregts and colleagues was identified from the literature and modified because some dietary variables were unavailable and to accord more closely with recommendations of the UK Committee on Medical Aspects of Food Policy. SUBJECTS: In total, 1475 traced, surviving cohort members aged 60 years and over. RESULTS: Modification resulted in a 12-item Healthy Diet Score (HDS). We found that about half the variation in the HDS was explained by variation in the HDI (r=0.71). There was, however, little misclassification of subjects (<10%) into extreme thirds of the distribution by the HDS compared with the HDI. Items of the score most strongly correlated with overall score were saturated fat (r=-0.57), red meat (r=-0.46), dietary fibre (r=0.58), fruit and vegetables (r=0.54) and percentage energy from carbohydrates (r=0.51). Modifying existing items had greater impact on agreement between HDI and HDS than the addition of new items. CONCLUSIONS: The selection and modification of diet scores is more complicated than often assumed. Furthermore, modest changes to an existing score can produce a score that is different from the original, and although it was not possible to test this issue, it may no longer predict subsequent health experience.

Life course influences on quality of life in early old age.

A growing literature demonstrates life course influences on health in early old age. The present paper is the first to examine whether similar processes also influence quality of life in early old age. The question is theorised in terms of structured dependency and third age, and the life course pathways by which people arrive at these destinations in later life. The issues are investigated in a unique data set that contains health and life course information on some 300 individuals mostly aged 65-75 years, enhanced in 2000 by postal survey data on quality of life. Several types of life course effect are identified at conventional levels of statistical significance. Long-term influences on quality of life, however, are less marked than those on health. Quality of life in early old age appears to be influenced primarily by current contextual factors such as material circumstances and serious health problems, with the influence of the life course limited mostly to its shaping of an individual's circumstances in later life. The implication for policy is that disadvantage during childhood and adulthood does not preclude good quality of life in early old age.

Background influences on dietary choice in early old age.

The contemporary increase in life expectancy is opening up a new stage in the Life course--early old age. Diet during early old age makes an important contribution to disease prevention, the management of established disease and postponing the onset of physical dependency. Despite its importance, few specifically medical, dietary interventions have been designed for this age group. The presently reported study aims to supply background information for such an endeavour. Qualitative interviews have been conducted with people in early old age, sampled purposively from members of a longitudinal study cohort. A number of background influences on the dietary choices of the interviewees have been identified. Some of these influences are specific to the present generation of people in early old age, such as eating in NAAFI canteens during National Service. However, the more general categories of which they are a part will have enduring usefulness. The findings are discussed in relation to: future dietary advice; the potential for interventions in primary care; enhancing the policy of free school fruit and research on the next age cohort to enter early old age.

A measure of quality of life in early old age: the theory, development and properties of a needs satisfaction model (CASP-19).

Quality of life is the subject of much research. However it lacks an agreed theoretical basis. In studies with older populations(ill) health has been used as a proxy measure for quality of life (QoL). We have developed a needs satisfaction measure of QoL in early old age. Our measure has four ontologically grounded domains: conal, autonomy, pleasure, and self-realization. The measure was piloted with focus groups, a self-completion pilot, and cognitive interview testing. This produced a 22-item scale that was included in a postal questionnaire and sent to 286 people aged 65-75 years.A 92% response rate was achieved. The scale was reduced to 19 items on the basis of statistical analysis. The domains have Cronbach's alphas between 0.6 and 0.8. Correlations between the four domains range from 0.4 to 0.7. A second order factor analysis revealed a single latent QoL factor. The scores for the 19-item scale are well distributed along the range although they exhibit a slight negative skew. Concurrent validity was assessed using the Life Satisfaction Index--wellbeing. A strong and positive association was found between the two scales (r= 0.6, p = 0.01). The CASP-19 appears to be a useful scale for measuring QoL in older people.

Domestic labour, paid employment and women's health: analysis of life course data.

The relationship between the amount of domestic labour performed by a woman during her lifetime and a variety of self-reported and objective measures of her health in early old age was examined in the female members (n = 155) of a data set containing considerable life course information, including full household, residential and occupational histories. Domestic labour, on its own, proved a weak predictor of health. The relationship strengthened when domestic labour was combined with the hazards of the formal paid employment which the woman had performed. This suggests that it is the combination of domestic labour plus paid employment which influences women's health. The robustness of this conclusion is indicated by its agreement with other studies which reached the same conclusion through an analysis of data with markedly different characteristics.

The "inverse housing law" and respiratory health.

STUDY OBJECTIVE: To investigate whether there is a mismatch within Britain between climate severity and housing quality ("inverse housing law") and whether this mismatch is associated with respiratory health. DESIGN, SETTING AND PARTICIPANTS: Cross sectional observational study. Britain (Scotland, Wales and England). The 3023 male and 3694 female Health and Lifestyle Survey participants with valid data available on all relevant items. MAIN RESULTS: Geographical mapping shows a mismatch between climate severity and housing quality. Individual level analysis shows that lung function is associated with climate and housing, and their interaction, independently of cigarette smoking status. The physical quality of the housing seems to be most important to respiratory health in areas with harsh climate. CONCLUSIONS: Interpretation must be cautious because cross sectional data have been used to investigate processes that are longitudinal and, possibly, selective. Nevertheless, there does seem to be an "inverse housing law", such that some of the worst quality housing is found in areas with severe climate; and, on the balance of probabilities, this inverse housing law affects respiratory health.

How accurately are height, weight and leg length reported by the elderly, and how closely are they related to measurements recorded in childhood?

BACKGROUND: This paper examines (1) the accuracy of self-reported height, leg length and weight in a group of subjects aged 56-78; (2) whether recent measurement of height and weight influences the accuracy of self-reporting and (3) associations between childhood and adult height, leg length and BMI measured in old age. METHODS: All 3182 surviving members of the Boyd Orr cohort were sent postal questionnaires in 1997-1998 and a sub-sample (294) was also clinically examined. RESULTS: Self-reported height was overestimated and body mass index (BMI), based on reported height and weight, underestimated. The mean difference between self-report and measured values were for height: 2.1 cm in males and 1.7 cm in females; for BMI the difference was -1.3 kg/m(2) in males and -1.2 kg/m(2) in females. Shorter individuals and older subjects tended to over-report their height more than others. The overweight under-reported their weight to a greater extent. Recent measurement appeared to decrease over-reporting of height but not weight. Correlations between self-report and measured height and BMI were generally over 0.90, but weaker for leg length (r = 0.70 in males and 0.71 in females). Adult height and leg length were quite closely related to their relative values in childhood (correlation coefficients ranged from 0.66 to 0.84), but associations between adult and childhood BMI were weak (r = 0.19 in males and 0.21 in females). CONCLUSIONS: Self-reported measures of height and weight may be used in studies of the elderly although systematic reporting errors may bias effect estimates. As overweight individuals tend to under-report and the short and underweight tend to over-report, studies investigating associations of disease with height and weight using self-reported measures will underestimate effects. The weak associations between childhood and adult BMI indicate that associations between childhood adiposity and adult cardiovascular disease found in this cohort may reflect the specific effect of childhood overweight, rather than its persistence into adulthood. This suggests that avoidance of adiposity may be as important in childhood as in adulthood.