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J Head

Publications and source records attributed to J Head.

At least 19 recordsLinked to original sources
PubMed2007

A multi-state model for joint modelling of terminal and non-terminal events with application to Whitehall II.

Serious coronary heart disease (CHD) is a primary outcome in the Whitehall II study, a large epidemiological study of British civil servants. Both fatal (F) and non-fatal (NF) CHD events are of interest and while essentially complete information is available on F events, the observation of NF events is subject to potentially informative censoring. A multi-state model with an unobserved state is introduced for the joint modelling of F and NF events. Two model-based assumptions ensure identifiability of the model and a parameter is introduced to allow sensitivity analyses concerning the assumption linked to informative censoring. Weibull transition rates, which include dependence on explanatory variables, are used in the analysis of Whitehall II data with a particular focus on the relationship between civil service grade and CHD events.

Adult↗
PubMed2006

Body mass, weight control behaviours, weight perception and emotional well being in a multiethnic sample of early adolescents.

OBJECTIVE: To investigate weight perception, dieting and emotional well being across the range of body mass index (BMI) in a population-based multiethnic sample of early adolescents. DESIGN: Cross-sectional population-based survey. SUBJECTS: In total, 2789 adolescents 11-14 years of age from three highly deprived regional authorities in East London, in 2001. MEASUREMENTS: Data were collected by student-completed questionnaire on weight perception, dieting history, mental and physical health, health behaviours, social capital and sociodemographic factors. Height and weight were measured by trained researchers. Overweight was defined as BMI > or =85th centile and obesity as BMI > or =98th centile. Underweight was defined as BMI< or =15th centile. RESULTS: In all, 73% were from ethnic groups other than white British. Valid BMI were available for 2522 subjects (90.4%) of whom 14% were obese. Only 20% of overweight boys and 51% of overweight girls assessed their weight accurately. Accuracy of weight perception did not vary between ethnic groups. In all, 42% of girls and 26% of boys reported current dieting to lose weight. Compared with white British teenagers, a history of dieting was more common among Bangladeshi, Indian and mixed ethnicity boys and less likely among Pakistani girls. Self-esteem was not associated with BMI in girls but was significantly lower in obese boys than those of normal weight (P=0.02). Within ethnic subgroups, self-esteem was significantly lower in overweight white British boys (P=0.03) and obese Bangladeshi boys (P=0.01) and Bangladeshi girls (P=0.04), but significantly higher in obese black African girls (P=0.01) than those of normal weight. Obese young people had a higher prevalence of psychological distress (P=0.04), except among Bangladeshi teenagers, where overweight and obese young people had less psychological distress than those of normal weight (P=0.02). Birth outside the UK was associated with reduced risk of obesity in girls (P=0.02) but not with history of dieting, weight perception or psychological factors in either gender. CONCLUSION: High levels of current dieting for weight control and inaccurate perception of body mass are common across all ethnic groups. However, dieting history and the associations of obesity with self-esteem and psychological distress vary between ethnic groups. Interventions to prevent or treat obesity in black or minority ethnicity groups must consider cultural differences in the relationship between body mass, self-esteem and psychological distress.

Adolescent↗
PubMed2006

Injustice at work and incidence of psychiatric morbidity: the Whitehall II study.

BACKGROUND: Previous studies of organisational justice and mental health have mostly examined women and have not examined the effect of change in justice. AIM: To examine effects of change in the treatment of employees by supervisors (the relational component of organisational justice) on minor psychiatric morbidity, using a cohort with a large proportion of men. METHODS: Data are from the Whitehall II study, a prospective cohort of 10 308 white-collar British civil servants (3143 women and 6895 men, aged 35-55 at baseline) (Phase 1, 1985-88). Employment grade, relational justice, job demands, job control, social support at work, effort-reward imbalance, physical illness, and psychiatric morbidity were measured at baseline. Relational justice was assessed again at Phase 2 (1989-90). The outcome was cases of psychiatric morbidity by Phases 2 and 3 (1991-93) among participants case-free at baseline. RESULTS: In analyses adjusted for age, grade, and baseline physical illness, women and men exposed to low relational justice at Phase 1 were at higher risk of psychiatric morbidity by Phases 2 and 3. Adjustment for other psychosocial work characteristics, particularly social support and effort-reward imbalance, partially attenuated these associations. A favourable change in justice between Phase 1 and Phase 2 reduced the immediate risk (Phase 2) of psychiatric morbidity, while an adverse change increased the immediate and longer term risk (Phase 3). CONCLUSION: This study shows that unfair treatment by supervisors increases risk of poor mental health. It appears that the employers' duty to ensure that employees are treated fairly at work also has benefits for health.

Adult↗
PubMed2006

Work stress, weight gain and weight loss: evidence for bidirectional effects of job strain on body mass index in the Whitehall II study.

OBJECTIVE: Previous research has focused on overall associations between work stress and body mass index (BMI) ignoring the possibility that stress may cause some people to eat less and lose weight and others to eat more. Using longitudinal data, we studied whether work stress induced weight loss in lean individuals and weight gain in overweight individuals. DESIGN: Prospective cohort study. SUBJECTS: A total of 7965 British civil servants (5547 men and 2418 women) aged 35-55 at study entry (The Whitehall II study). MEASUREMENTS: Work stress, indicated by the job strain model and measured as job control, job demands and job strain, was assessed at baseline and BMI at baseline and at 5-year follow-up. RESULTS: In men, the effect of job strain on weight gain and weight loss was dependent on baseline BMI (P</=0.03). In the leanest quintile (BMI<22 kg/m(2)) at baseline, high job strain and low job control were associated with weight loss by follow-up, whereas among those in the highest BMI quintile (>27 kg/m(2)), these stress indicators were associated with subsequent weight gain. No corresponding interaction was seen among women. CONCLUSION: Inconsistent findings reported by previous studies of stress and BMI have generally been interpreted to indicate the absence of an association. In light of our results, the possibility of differential effects of work stress should also be taken into account.

Adult↗
PubMed2005

A comparison of self-reported sickness absence with absences recorded in employers' registers: evidence from the Whitehall II study.

AIM: To compare self-reported sickness absence days in the last 12 months with recorded absences from the employers' registers for the same period. METHODS: Self-reported sickness absence data over the 12 months preceding baseline (1985-88) were compared with absence records from the employers' registers over the same period for 2406 women and 5589 men, participants in the Whitehall II study of British civil servants. Associations with self-rated health, longstanding illness, minor psychiatric disorder, physical illness, and prevalent coronary heart disease at baseline were determined. RESULTS: In general, women reported less sickness absence over the last year than was recorded in the employers' registers, while men, with the exception of those in the lower employment grades, reported more. Agreement between self-reported and recorded absence days decreased as the total number of days increased. After adjustment for employment grade and the average number of recorded and self-reported absence days, the total number of self-reported absence days was within two days of the recorded number of days for 63% of women and 67% of men. Associations between annual self-reported sickness absence days and self-rated health, longstanding illness, minor psychiatric disorder, physical illness, and prevalent coronary heart disease were as strong as those for recorded absence days. CONCLUSION: These findings suggest that agreement between the annual number of self-reported and the annual number of recorded sickness absence days is relatively good in both sexes and that associations with health are equivalent for both measures.

Absenteeism↗
PubMed2004

Social position and minor psychiatric morbidity over time in the British Household Panel Survey 1991-1998.

STUDY OBJECTIVE: To examine social inequalities in minor psychiatric morbidity as measured by the GHQ-12 using lagged models of psychiatric morbidity and changing job status. DESIGN: GHQ scores were modelled using two level hierarchical regression models with measurement occasions nested within individuals. The paper compares and contrasts three different ways of describing social position: income, social advantage and lifestyle (the Cambridge scale), and social class (the new National Statistics Socio-Economic Classification), and adjusts for attrition. SETTING: Survey interviews for a nationally representative sample of adults of working age living in Britain. PARTICIPANTS: 8091 original adult respondents in 1991 who remain of working age during 1991-1998 from the British Household Panel Survey (BHPS). MAIN RESULTS: There was a relation of GHQ-12 to social position when social position was combined with employment status. This relation itself varied according to a person's psychological health in the previous year. CONCLUSIONS: The relation between social position and minor psychiatric morbidity depended on whether or not a person was employed, unemployed, or economically inactive. It was stronger in those with previously less good psychological health. Among employed men and women in good health, GHQ-12 varied little according to social class, status, or income. There was a "classic" social gradient in psychiatric morbidity, with worse health in less advantaged groups, among the economically inactive. Among the unemployed, a "reverse" gradient was found: the impact of unemployment on minor psychiatric morbidity was higher for those who were previously in a more advantaged social class position.

Adult↗
PubMed2004

The psychosocial work environment and alcohol dependence: a prospective study.

AIMS: To examine whether a stressful psychosocial work environment predicts alcohol dependence. METHODS: Alcohol dependence of participants in the Whitehall II occupational cohort of London based civil servants (1985-88) was measured in 1991-93 using the CAGE questionnaire. The psychosocial work environment was measured by self report questions on the job demand-support-control model and on the model of effort-reward imbalance. Potential mediators including physical illness and poor mental health (GHQ) were measured at follow up in 1989. RESULTS: Effort-reward imbalance at work was associated with alcohol dependence in men after adjustment for employment grade and other baseline factors related to alcohol dependence. Although effort-reward imbalance predicted future longstanding illness, poor mental health and negative aspects of close relationships, the association between effort-reward imbalance and alcohol dependence in men was only partially mediated through these health and social support measures. In women, low decision latitude was related to alcohol dependence to some extent, but alcohol dependence among women was more prevalent in higher occupational grades. Men with high job demands or with low work social supports had a slightly reduced risk of alcohol dependence. No association was found between objectively assessed demands, job control, and alcohol dependence in either men or women. CONCLUSION: A stressful psychosocial work environment in terms of effort-reward imbalance was found to be a risk factor for alcohol dependence in men. In view of the public health importance of alcohol dependence in working populations these findings call for more emphasis on psychosocial factors in occupational health research and prevention.

Adult↗
PubMed2003

TRPV1 receptors mediate particulate matter-induced apoptosis.

Exposure to airborne particulate matter (PM) is a world-wide health problem mainly because it produces adverse cardiovascular and respiratory effects that frequently result in morbidity. Despite many years of epidemiological and basic research, the mechanisms underlying PM toxicity remain largely unknown. To understand some of these mechanisms, we measured PM-induced apoptosis and necrosis in normal human airway epithelial cells and sensory neurons from both wild-type mice and mice lacking TRPV1 receptors using Alexa Fluor 488-conjugated annexin V and propidium iodide labeling, respectively. Exposure of environmental PMs containing residual oil fly ash and ash from Mount St. Helens was found to induce apoptosis, but not necrosis, as a consequence of sustained calcium influx through TRPV1 receptors. Apoptosis was completely prevented by inhibiting TRPV1 receptors with capsazepine or by removing extracellular calcium or in sensory neurons from TRPV1(-/-) mice. Binding of either one of the PMs to the cell membrane induced a capsazepine-sensitive increase in cAMP. PM-induced apoptosis was augmented upon the inhibition of PKA. PKA inhibition on its own also induced apoptosis, thereby suggesting that this pathway may be endogenously protective against apoptosis. In summary, it was found that inhibiting TRPV1 receptors prevents PM-induced apoptosis, thereby providing a potential mechanism to reduce their toxicity.

Air Pollutants↗
PubMed2003

Social inequalities in depressive symptoms and physical functioning in the Whitehall II study: exploring a common cause explanation.

STUDY OBJECTIVE: This study investigated which risk factors might explain social inequalities in both depressive symptoms and physical functioning and whether a common set of risk factors might account for the association between depressive symptoms and physical functioning. DESIGN: A longitudinal prospective occupational cohort study of female and male civil servants relating risk factors at baseline (phase 1: 1985-8) to employment grade gradients in depressive symptoms and physical functioning at follow up (phase 5: 1997-9). Analyses include the 7270 men and women who participated at phase 5. SETTING: Whitehall II Study: 20 London based white collar civil service departments. PARTICIPANTS: Male and female civil servants, 35-55 years at baseline. MAIN RESULTS: Depressive symptoms were measured by a subscale of items from the 30 item General Health Questionnaire. Physical functioning was measured by a subscale of the SF-36. Employment grade was used as a measure of socioeconomic position as it reflects both income and status. The grade gradient in depressive symptoms was entirely explained by risk factors including work characteristics, material disadvantage, social supports, and health behaviours. These risk factors only partially explained the gradient in physical functioning. The correlation between depressive symptoms and physical functioning was reduced by adjustment for risk factors and baseline health status but not much of the association was explained by adjustment for risk factors. Among women, the association between depression and physical functioning was significantly stronger in the lower grades both before and after adjustment for risk factors and baseline health. For women, there was only a significant grade gradient in depressive symptoms among those reporting physical ill health. CONCLUSIONS: Some risk factors contribute jointly to the explanation of social inequalities in mental and physical health although their relative importance differs. Work is most important for inequalities in depressive symptoms in men, and work and material disadvantage are equally important in explaining inequalities in depressive symptoms in women while health behaviours are more important for explaining inequalities in physical functioning. These risk factors did not account for the association between mental health and physical health or the greater comorbidity seen in women of lower socioeconomic status. The risk of secondary psychological distress among those with physical ill health is greater in the low employment grades.

Adult↗
PubMed2002

Multilevel modelling of aircraft noise on performance tests in schools around Heathrow Airport London.

STUDY OBJECTIVE: To examine the effects of chronic exposure to aircraft noise on children's school performance taking into account social class and school characteristics. DESIGN: This is a cross sectional study using the National Standardised Scores (SATs) in mathematics, science, and English (11 000 scores from children aged 11 years). The analyses used multilevel modelling to determine the effects of chronic aircraft noise exposure on childrens' school performance adjusting for demographic, socioeconomic and school factors in 123 primary schools around Heathrow Airport. Schools were assigned aircraft noise exposure level from the 1994 Civil Aviation Authority aircraft noise contour maps. SETTING: Primary schools. PARTICIPANTS: The sample were approximately 11 000 children in year 6 (approximately 11 years old) from 123 schools in the three boroughs surrounding Heathrow Airport. MAIN RESULTS: Chronic exposure to aircraft noise was significantly related to poorer reading and mathematics performance. After adjustment for the average socioeconomic status of the school intake (measured by percentage of pupils eligible for free school meals) these associations were no longer statistically significant. CONCLUSIONS: Chronic exposure to aircraft noise is associated with school performance in reading and mathematics in a dose-response function but this association is confounded by socioeconomic factors.

Aircraft↗
PubMed2001

Ten-year follow-up of three different initial treatments in de-novo PD: a randomized trial.

BACKGROUND: The long-term effectiveness of three different initial drug regimes in patients with early, mild PD was evaluated by the PD Research Group of the United Kingdom (PDRGUK). In 1995, the selegiline arm of the trial was terminated following an interim analysis. METHOD: This was an open, randomized trial. Between 1985 and 1990, 782 patients with de-novo PD were recruited and randomized to one of three treatment arms: levodopa plus dopa decarboxylase inhibitor; levodopa plus decarboxylase inhibitor and selegiline; or bromocriptine. The main endpoints were mortality, disability, and adverse events. Intention-to-treat analysis was used. RESULTS: There was no significant difference in mortality between the bromocriptine and the levodopa arms (hazard ratio 1.15 [95% CI 0.90, 1.47]). Patients initially randomized to bromocriptine had slightly worse disability scores throughout follow-up. This difference was significant during the first years. Patients in the bromocriptine arm returned to pretreatment disability levels one year earlier than those in the levodopa arm. Patients randomized to bromocriptine had a significantly lower incidence of dyskinesias than those randomized to levodopa (rate ratio 0.73 [95% CI 0.57, 0.93]). However, this difference was not significant when only moderate to severe dyskinesias were considered. Patients in the bromocriptine arm had slightly lower rates of dystonias and on-off fluctuations, but moderate and severe forms were equally frequent in both arms. CONCLUSION: Starting treatment with the dopamine agonist bromocriptine does not reduce mortality in PD. A slightly lower incidence of motor complications is achieved at the expense of significantly worse disability scores throughout the first years of therapy.

Antiparkinson Agents↗
PubMed2001

Chronic aircraft noise exposure, stress responses, mental health and cognitive performance in school children.

BACKGROUND: Previous research suggests that children are a high risk group vulnerable to the effects of chronic noise exposure. However, questions remain about the nature of the noise effects and the underlying causal mechanisms. This study addresses the effects of aircraft noise exposure on children around London Heathrow airport, in terms of stress responses, mental health and cognitive performance. The research also focuses on the underlying causal mechanisms contributing to the cognitive effects and potential confounding factors. METHODS: The cognitive performance and health of 340 children aged 8-11 years attending four schools in high aircraft noise areas (16 h outdoor Leq > 66 dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16 h outdoor Leq < 57 dBA). Mental health and cognitive tests were group administered to the children in the schools. Salivary cortisol was measured in a subsample of children. RESULTS: Chronic aircraft noise exposure was associated with higher levels of noise annoyance and poorer reading comprehension measured by standardized scales with adjustments for age, deprivation and main language spoken. Chronic aircraft noise was not associated with mental health problems and raised cortisol secretion. The association between aircraft noise exposure and reading comprehension could not be accounted for by the mediating role of annoyance, confounding by social class, deprivation, main language or acute noise exposure. CONCLUSIONS: These results suggest that chronic aircraft noise exposure is associated with impaired reading comprehension and high levels of noise annoyance but not mental health problems in children.

Aircraft↗
PubMed2001

The West London Schools Study: the effects of chronic aircraft noise exposure on child health.

BACKGROUND: Previous field studies have indicated that children's cognitive performance is impaired by chronic aircraft noise exposure. However, these studies have not been of sufficient size to account adequately for the role of confounding factors. The objective of this study was to test whether cognitive impairments and stress responses (catecholamines, cortisol and perceived stress) are attributable to aircraft noise exposure after adjustment for school and individual level confounding factors and to examine whether children exposed to high levels of social disadvantage are at greater risk of noise effects. METHODS: The cognitive performance and health of 451 children aged 8-11 years, attending 10 schools in high aircraft noise areas (16 h outdoor Leq > 63 dBA) was compared with children attending 10 matched control schools exposed to lower levels of aircraft noise (16 h outdoor Leq < 57 dBA). RESULTS: Noise exposure was associated with impaired reading on difficult items and raised annoyance, after adjustment for age, main language spoken and household deprivation. There was no variation in the size of the noise effects in vulnerable subgroups of children. High levels of noise exposure were not associated with impairments in mean reading score, memory and attention or stress responses. Aircraft noise was weakly associated with hyperactivity and psychological morbidity. CONCLUSIONS: Chronic noise exposure is associated with raised noise annoyance in children. The cognitive results indicate that chronic aircraft noise exposure does not always lead to generalized cognitive effects but, rather, more selective cognitive impairments on difficult cognitive tests in children.

Aviation↗
PubMed2001

A follow-up study of effects of chronic aircraft noise exposure on child stress responses and cognition.

BACKGROUND: Children are a high-risk group vulnerable to the effects of chronic aircraft noise exposure. This study examines the effects of aircraft noise exposure on children's health and cognition around London Heathrow airport and tests sustained attention as an underlying mechanism of effects of noise on reading and examines the way children adapt to continued exposure to aircraft noise. METHODS: In this repeated measures epidemiological field study, the cognitive performance and health of 275 children aged 8-11 years attending four schools in high aircraft noise areas (16-h outdoor Leq > 66 dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16-h outdoor Leq < 57 dBA). The children first examined at baseline were examined again after a period of one year at follow-up. Health questionnaires and cognitive tests were group administered to the children in the schools. RESULTS AND CONCLUSIONS: At follow-up chronic aircraft noise exposure was associated with higher levels of annoyance and perceived stress, poorer reading comprehension and sustained attention, measured by standardized scales after adjustment for age, social deprivation and main language spoken. These results do not support the sustained attention hypothesis previously used to account for the effects of noise on cognition in children. The reading and annoyance effects do not habituate over a one-year period and do not provide strong evidence of adaptation.

Adaptation, Psychological↗
PubMed2000

Probing meiosis in hybrids of Lolium (Poaceae) with a discriminatory repetitive genomic sequence.

A moderately repetitive genomic DNA sequence (designated pLPBB2-123) derived from Lolium perenne L. (Poaceae) is considerably more abundant in the genome of this species than in that of the closely related L. temulentum. The repetitive sequence probe is clearly able to discriminate between the genomic DNA of both species in Southern analysis, and effectively 'paints' only the chromosome set of L. perenne in diploid and triploid hybrids with L. temulentum. Fluorescence in situ hybridisation of this sequence onto homologous chromosomes during meiosis I of the hybrids shows that the sequence is evenly distributed along all of the chromosomes of L. perenne and appears to have little effect on the structural integrity or recombination potential of hybrid bivalents. Discrimination between chromatin of different parental origin in hybrid bivalents shows for the first time a progressive relaxation of relational coiling of homoeologues throughout meiotic prophase. It also highlights structural irregularities that can now be unequivocally assigned to the longer chromosomes of L. temulentum. The advantages of the use of specific differentially amplified sequences instead of whole genome probes are discussed within the context of introgression breeding programmes within the Lolium/Festuca complex.

Chromosomes↗