Characteristics of a protocol to collect objective physical activity/sedentary behaviour data in a large study: Seniors USP (understanding sedentary patterns)

The Seniors USP study measured sedentary behaviour (activPAL3, 9 day wear) in older adults. The measurement protocol had three key characteristics: enabling 24-hour wear (monitor location, waterproofing); minimising data loss (reducing monitor failure, staff training, communication); and quality assurance (removal by researcher, confidence about wear). Two monitors were not returned; 91% (n=700) of returned monitors had 7 valid days of data. Sources of data loss included monitor failure (n=11), exclusion after quality assurance (n=5), early removal for skin irritation (n=8) or procedural errors (n=10). Objective measurement of physical activity and sedentary behaviour in large studies requires decisional trade-offs between data quantity (collecting representative data) and utility (derived outcomes that reflect actual behaviour).

Systematic comparative validation of self-report measures of sedentary time against an objective measure of postural sitting (activPAL)

BACKGROUND

Sedentary behaviour is a public health concern that requires surveillance and epidemiological research. For such large scale studies, self-report tools are a pragmatic measurement solution. A large number of self-report tools are currently in use, but few have been validated against an objective measure of sedentary time and there is no comparative information between tools to guide choice or to enable comparison between studies. The aim of this study was to provide a systematic comparison, generalisable to all tools, of the validity of self-report measures of sedentary time against a gold standard sedentary time objective monitor.

METHODS

Cross sectional data from three cohorts (N = 700) were used in this validation study. Eighteen self-report measures of sedentary time, based on the TAxonomy of Self-report SB Tools (TASST) framework, were compared against an objective measure of postural sitting (activPAL) to provide information, generalizable to all existing tools, on agreement and precision using Bland-Altman statistics, on criterion validity using Pearson correlation, and on data loss.

RESULTS

All self-report measures showed poor accuracy compared with the objective measure of sedentary time, with very wide limits of agreement and poor precision (random error > 2.5 h). Most tools under-reported total sedentary time and demonstrated low correlations with objective data. The type of assessment used by the tool, whether direct, proxy, or a composite measure, influenced the measurement characteristics. Proxy measures (TV time) and single item direct measures using a visual analogue scale to assess the proportion of the day spent sitting, showed the best combination of precision and data loss. The recall period (e.g. previous week) had little influence on measurement characteristics.

CONCLUSION

Self-report measures of sedentary time result in large bias, poor precision and low correlation with an objective measure of sedentary time. Choice of tool depends on the research context, design and question. Choice can be guided by this systematic comparative validation and, in the case of population surveillance, it recommends to use a visual analog scale and a 7 day recall period. Comparison between studies and improving population estimates of average sedentary time, is possible with the comparative correction factors provided.

Why is Mini-Mental state examination performance correlated with estimated premorbid cognitive ability?

BACKGROUND

Tests requiring the pronunciation of irregular words are used to estimate premorbid cognitive ability in patients with clinical diagnoses, and prior cognitive ability in normal ageing. However, scores on these word-reading tests correlate with scores on the Mini-Mental State Examination (MMSE), a widely used screening test for possible cognitive pathology. This study aimed to test whether the word-reading tests' correlations with MMSE scores in healthy older people are explained by childhood IQ or education.

METHOD

Wechsler Test of Adult Reading (WTAR), National Adult Reading Test (NART), MMSE scores and information about education were obtained from 1024 70-year-olds, for whom childhood intelligence test scores were available.

RESULTS

WTAR and NART were positively correlated with the MMSE (r ≈ 0.40, p < 0.001). The shared variance of WTAR and NART with MMSE was significantly attenuated by ~70% after controlling for childhood intelligence test scores. Education explained little additional variance in the association between the reading tests and the MMSE.

CONCLUSIONS

MMSE, which is often used to index cognitive impairment, is associated with prior cognitive ability. MMSE score is related to scores on WTAR and NART largely due to their shared association with prior ability. Obtained MMSE scores should be interpreted in the context of prior ability (or WTAR/NART score as its proxy).

Changes in weight and waist circumference over 9 years in a Scottish population

OBJECTIVE

To document patterns of measured weight and waist circumference (WC) change and the increase in overweight and obesity over a 9-year period.

SUBJECTS/METHODS

A total of 1044 subjects from two age-defined cohorts aged 39 and 59 in 1991. Height, weight and WC were measured in 1991, 1995 and 2000 and body mass index (BMI) was calculated. Pattern of weight and WC change was studied over approximately 9 years.

RESULTS

The prevalence of overweight and obesity increased markedly and the younger cohort showed greater increases in weight and WC than the older cohort. There was no significant difference in mean BMI and/or mean 9-year weight change between men and women in either age cohort, and mean weight gain was similar for all occupational groups. Only 20% of subjects maintained a stable weight (+/-2 kg), while 42.2 and 17.6% gained greater than 5 and 10 kg over the 9-year period, respectively. The rate of weight gain appeared to be relatively steady over the 9 years among younger subjects but declined in the older subjects in the second half of the observation period.

CONCLUSIONS

Health promotion strategies to prevent weight gain need to be population-based, targeting all social and age groups, but particularly those in their early middle-age.

Social class, sex, and age differences in mucosal immunity in a large community sample

There have been very few reports addressing levels and distribution of commonly used PNI measures in large community samples. In this study, we report such data for secretion rates of secretory immunoglobulin A (sIgA), as determined from saliva samples taken from 1971 subjects interviewed as part of the West of Scotland Twenty-07 survey of health in West Central Scotland. Univariate analyses of demographic variables found lower sIgA and salivary flow to be significantly related to poorer social class, increased age, and being female. Smokers also had lower sIgA but not lower salivary flow. Multivariate analysis showed that demographic variables were significant predictors of sIgA independently of each other and assay variation. Adding smoking status to the equation confirmed it as an independent predictor and also indicated that social class differences in sIgA are partly explicable in terms of smoking status. In view of reported associations between sIgA levels and stress, its role as a first line of mucosal defense, and its relevance to health, these first results from a large survey are of interest. Further work is now needed to explore which factors, including psychosocial ones, may be contributing to subgroup differences.

A confirmatory factor analysis of the Hospital Anxiety and Depression scale: comparing empirically and theoretically derived structures

OBJECTIVES

To compare the fit of various factor solutions for the Hospital Anxiety and Depression scale (HAD; Zigmond & Snaith, 1983).

DESIGN

A cross-sectional postal survey was used to collect the data from community-based participants in the West of Scotland Twenty-07 study.

METHODS

The HAD scale, a 14-item self-administered measure of anxiety and depression, was completed by 2547 participants from three age cohorts (aged approximately 18, 39 and 58 years). Using confirmatory factor analyses four models suggested by prior exploratory factor analyses were compared to a model derived from Clark and Watson's (1991) tripartite theory of anxiety and depression.

RESULTS

The model derived from the tripartite theory of anxiety and depression (with factors labelled negative affectivity, anhedonic depression and autonomic anxiety) produced the closest fit to the data. This model produced a good fit in all three cohorts although group comparisons suggested that there were variations in the strength of some factor loadings across the three age groups. A model that had a hierarchical arrangement of the three factors in the tripartite model was also produced. This model fit the data equally as well as did the 'flat' tripartite model.

CONCLUSIONS

Three factors appear to underlie the HAD scale. Research is needed that examines whether or not using sub-scales based on these factors increases the ability of the HAD scale to detect cases of anxiety and depression.

Patterns and predictors of tobacco consumption among women

The study examines the patterns and predictors of cigarette consumption among 920 female smokers aged 16-49 who formed part of the British Household Panel Survey, a representative survey of households in Britain. The study assesses the influence of three key factors: socio-economic circumstances, psychological health and partner's smoking status. The study confirms that female smokers are more disadvantaged than the broader population of women, both with respect to their socio-economic circumstances and their psychological health. Within this disadvantaged group, higher cigarette consumption was linked to greater socio-economic disadvantage and poorer psychological health but not partner's smoking status. Age and pregnancy status also had an independent effect on consumption. Of these factors, being in poor psychological health was the single most powerful predictor of high rates of consumption. The implications of the findings for health promotion are discussed.

The first contact of patients with schizophrenia with psychiatric services: social factors and pathways to care in a multi-ethnic population

BACKGROUND

African-Caribbean patients have less desirable routes of entry into the psychiatric services than other ethnic groups in Britain but this may not apply to the first contact with services.

METHODS

Patients' pathways to care, type of admission or referral and sectioning details were recorded for all first contact patients presenting to south London psychiatric services over a 2-year period. We also conducted a retrospective analysis of data from the Camberwell Register, comparing rates of compulsory admission between 'Whites' and 'African-Caribbeans' for first and readmissions, over a 20-year period.

RESULTS

Our first contact sample comprised 38 White, 38 African-Caribbean and 24 Asian patients with CATEGO defined broad schizophrenia. GP referral was found to be the most common mode of contact and there were no significant differences between the ethnic groups with regard to compulsory admission. Similarly, data from the Camberwell Register showed no significant difference in rates of compulsory admission between first admission White and African-Caribbean patients. However, when all readmissions were examined, African-Caribbeans were more likely to be admitted involuntarily.

CONCLUSIONS

Our findings suggest that reports of less desirable routes of entry for African-Caribbean patients into the psychiatric service do not apply to their first admission but are likely to develop over time and repeated contact with the services.

Do housing tenure and car access predict health because they are simply markers of income or self esteem? A Scottish study

OBJECTIVE

To investigate relations between health (using a range of measures) and housing tenure or car access; and to test the hypothesis that observed relations between these asset based measures and health are simply because they are markers for income or self esteem.

DESIGN

Analysis of data from second wave of data collection of West of Scotland Twenty-07 study, collected in 1991 by face to face interviews conducted by nurse interviewers.

SETTING

The Central Clydeside Conurbation, in the West of Scotland.

SUBJECTS

785 people (354 men, 431 women) in their late 30s, and 718 people (358 men, 359 women) in their late 50s, participants in a longitudinal study.

MEASURES

General Health Questionnaire scores, respiratory function, waist/hip ratio, number of longstanding illnesses, number of symptoms in the last month, and systolic blood pressure; household income adjusted for household size and composition; Rosenberg self esteem score; housing tenure and care access.

RESULTS

On bivariate analysis, all the health measures were significantly associated with housing tenure, and all except waist/hip ratio with car access; all except waist/hip ratio were related to income, and all except systolic blood pressure were related to self esteem. In models controlling for age, sex, and their interaction, neither waist/hip ratio nor systolic blood pressure remained significantly associated with tenure or care access. Significant relations with all the remaining health measures persisted after further controlling for income or self esteem.

CONCLUSIONS

Housing tenure and car access may not only be related to health because they are markers for income or psychological traits; they may also have some directly health promoting or damaging effects. More research is needed to establish mechanisms by which they may influence health, and to determine the policy implications of their association with health.

Incidence and outcome of schizophrenia in whites, African-Caribbeans and Asians in London

BACKGROUND

Several previous studies have indicated high rates of schizophrenia in African-Caribbeans in the UK compared to White population.

METHOD

All people aged 18 to 64 years residing in two health districts in London who made contact with hospital or community services over a 1-year (Whites) or 2-year (ethnic minorities) period were screened for psychotic symptoms.

RESULTS

One hundred and twenty-three patients passed the screen, of whom 100 were assigned a schizophrenic class by the CATEGO program. Of these, 38 were White, 38 African-Caribbean and 24 Asian. The incidence rate for broad schizophrenia was significantly higher for African-Caribbeans than for Whites. Asians showed a high rate among people age 30 and over, particularly women. Poor outcome at 1-year follow-up was significantly more common for African-Caribbeans than for the other two groups. The proportion of African-Caribbeans with a poor outcome was two and a half times greater than that of Whites. On a range of seven socio-demographic variables, African-Caribbeans differed from the other two groups only on unemployment.

CONCLUSIONS

A multitide of factors play a role in the aetiology of schizophrenia. Comparison of environmental factors in these groups may identify factors that contribute to the aetiology of schizophrenia.

First-contact incidence rates of schizophrenia in Trinidad and one-year follow-up

BACKGROUND

Incidence rates of schizophrenia among UK African-Caribbeans have been reported as high. Various explanations including selective migration and genetic vulnerability have been proposed.

METHOD

In one calendar year, all new cases of psychosis presenting to various psychiatric services in two clearly defined geographical catchment areas in Trinidad-one in the rural south and the other an urban area-were studied. Standardised diagnostic instruments were applied and information collected using WHO screening and measurement instruments.

RESULTS

A total of 56 cases were collected, giving an incidence rate of 2.2/1000 of broad schizophrenia with a rate of 1.6 for S+ schizophrenia.

CONCLUSION

These rates are similar to those from the WHO study in Honolulu and Aarhus, and much lower than the rates for African-Caribbeans in London. The cases were followed up for one year and the poor outcome rate for schizophrenia was 19%. The findings are discussed in a cross-cultural context and suggestions for future research made.

The incidence of mania: time trends in relation to gender and ethnicity

In order to investigate conflicting reports about possible changes in the incidence of mania, we established first contact rates for mania in the defined area of Camberwell between 1965 and 1984. There was some evidence for an increase in the first contact rate of mania, especially in females. This rise may be associated with the influx into Camberwell of individuals of Afro-Caribbean origin who showed significantly higher rates than the white group [adjusted rate ratio 3.1; 95% confidence interval (CI) 1.4-6.9] and more often displayed mixed manic and schizophrenic symptomatology (risk ratio 2.2; 95% CI 1.1-4.3). We conclude that the incidence of mania has not decreased and may actually have increased. High rates of mental illness among members of ethnic minorities are not specific to schizophrenia, suggesting that a risk factor common to both manic and schizophrenic illness is more prevalent among these groups.

Psychotic illness in ethnic minorities: clarification from the 1991 census

Age and sex-adjusted first admission rates for operationally-defined schizophrenia and other non-affective psychosis in different ethnic groups were calculated over the period 1988-1992 in a defined catchment area in South London. Standardized rates for schizophrenia, corrected for age- and gender-related under-reporting in the 1991 census and a 20% underestimate of the size of the ethnic minority populations in the area, were not only higher in the Afro-Caribbean group (SMR: 3.1; 95% C1:2.0-4.7), but also in the African group (SMR: 4.2; 95% C1: 2.8-6.2). It was further found that higher rates were not specific to schizophrenia. These findings suggest that some common factor associated with ethnic minority membership is important in producing an excess of psychotic illness.

Premorbid abnormalities in mania, schizomania, acute schizophrenia and chronic schizophrenia

The aim of this study was to examine the hypothesis that differences in outcome among affective and non-affective psychoses are associated with differences in the degree of developmental deviance. We conducted a retrospective survey of first contact cases treated over a 20-year period in a psychiatric hospital serving a catchment area in South London. All patients with non-depressive functional psychosis residing in the catchment area who received their first psychiatric treatment between 1965 and 1984 were included in the study. Cases were classified according to the relative chronicity of their illness into four non-overlapping groups: mania, schizomania, acute schizophrenia and chronic schizophrenia. There was a linear trend in the association between illness chronicity and proxy measures of development deviance, such as premorbid unemployment, single status and poor academic achievement. Compared to individuals with mania, schizophrenic patients had a 3-6 times increased risk of premorbid abnormality. For patients with schizomania and acute schizophrenia, the risk was 1.5-3 times greater than for manic subjects. We conclude that the prevalence of premorbid abnormalities is highest among chronic schizophrenia, but similar disturbances also occur, to a lesser degree, in less disabling affective and non-affective psychotic disorders.

Stress incubation and the onset of affective disorders

Incubation is the process by which life events influence the onset of psychiatric disorder after an appreciable delay. It has long been recognised clinically. In this paper we use data from the Camberwell Collaborative Depression Study to see whether incubation effects can be demonstrated in depressive illness. We used a novel adaptation of survival analysis for this purpose. The results suggest that incubation does occur in depressive disorder, that it is much less important than the effect of life events close to onset, that it is apparent in women but not in men, and that it is no more evident preceding endogenous than neurotic symptom patterns.

Schizophrenia and Afro-Caribbeans. A case-control study

A case-control study was performed using 90% of all first-contact patients with a clinical diagnosis of schizophrenia residing in the London borough of Camberwell between 1965 and 1984. Cases and controls were obtained from the Camberwell psychiatric case register. Controls were those presenting with first episodes of non-psychotic disorders, matched for age, sex and period. The risk of schizophrenia was greater in those of Afro-Caribbean ethnicity, irrespective of age, gender or place of birth. This risk increased over the study period. The results cannot be explained by changes in the age, gender or ethnic structure of the local population. Effects of misdiagnosis or change in diagnostic practice were reduced by using uniform operational criteria. Possible explanations include maternal exposure to unfamiliar infective agents, a differential fall in the age at onset of illness, or worsening social adversity.

The incidence of operationally defined schizophrenia in Camberwell, 1965-84

We established first-contact rates of schizophrenia in the defined area of Camberwell between 1965 and 1984. The rate of schizophrenia, whether defined by ICD, RDC, or DSM-III criteria, rose over the period under study. This finding is at odds with reports of an overall decline in first-admission rates for schizophrenia in England, over the same period. The discrepancy was largely accounted for by the influx into Camberwell of individuals of Afro-Caribbean origin, who showed rates of schizophrenia between four and eight times that of their Caucasian counterparts.

Gender, parity and the prevalence of minor affective disorder

Data from a two-stage survey of the general population were used to test the proposition that the over-representation of minor affective disorders among women was restricted to those who had had children, independently of current involvement in childcare. Initial analyses supported this proposition strongly. Subsequent linear logistic analyses were largely in favour of an effect of marriage rather than of parity, but it remains possible that part of the gender differences in rates of depression arises because of the effect of parity in raising female prevalence. If substantiated, the parity effect could operate through social or biological mechanisms; although its nature is unclear, it merits further investigation.

Is schizophrenia disappearing?

The incidence of schizophrenia is regarded as being similar between different cultures and times. However, several studies, mostly based on first-admission rates, have suggested that the incidence has declined over the past 10-15 years. Data from England and Wales for 1952-86 have been examined: there has been a substantial decrease, beginning in the mid-1960s, in the incidence of schizophrenia.

Season of birth in Alzheimer's disease

Variation in quarter of birth was examined in patients with a clinical diagnosis of AD. There was a significant excess of first-quarter births among AD patients as compared with the expected birth rates derived from an age-matched census sample. This finding was due entirely to the significant excess of first-quarter births in AD patients without a family history of dementia. No seasonal variation was found in the birth dates of other clinical groups.

The structure and validity of acculturation. Analysis of an acculturation scale

This paper presents data from a study of acculturation in 291 Greek Cypriot immigrants from the general population of Camberwell, south London. Factor analysis was carried out, and factors were extracted using the maximum likelihood method and subjected to oblique rotation. The best solution was based on two highly correlated factors (0.64), which together explained 28% of the variance. The first factor appeared to represent Cultural Identification, the second, Language Mastery/Ethnocentricism. The construct validity of the factors was substantiated by analyses relating them to a range of other variables likely to be correlated with acculturation. Issues concerning the measurement of acculturation are discussed.

Adversity and working class vulnerability to minor affective disorder

In this paper, we examine the proposition that members of lower social classes are more likely than those from higher classes to develop minor affective disorders in the face of adverse experiences. This was examined using data from a psychiatric survey of the general population of Camberwell, S.E. London, U.K. Working class subjects experienced significantly more adversity than their middle class counterparts. However, the relationship between life events and psychiatric disorder was consistent and considerable in the working class group. It was attenuated or non-existent in middle class subjects, depending on the particular categorisation of the data. Log-linear analyses suggested that the basis of this finding was unclear. Both the results and the underlying reasons for them merit further investigation.

How depressing life is--life-long morbidity risk for depressive disorder in the general population

We present estimates of lifetime risk and of cumulative risk up to each age for depressive disorder for the population of an inner city area (Camberwell, SE London). Estimates are based on an incidence study for the year 1976 which drew from the records of a case register. The estimates of lifetime risk obtained, 12% for men and 20% for women, are similar to those previously published in the literature. Inception risk by age and risks for in-patient treatment are also presented for men and women. The method of calculation is discussed and we show how to obtain an upper limit for the effect of the increased mortality associated with the disorder. We noted an apparent decline over the 'seventies' in inception rates for depression, and we consider the comparability of our statistics with risks calculated using complete psychiatric history data.