Accumulation of factors influencing respiratory illness in members of a national birth cohort and their offspring

A lifecourse approach in examining the association between accumulation of adversity and mental health in older adulthood

BACKGROUND

There is evidence for a cumulative effect of adversities on mental health, however, less is known on the accumulating duration of exposure to adversity across the lifecourse on mental health in older adults.

METHODS

Using data from the 1946 British birth cohort study (N = 2745), we examined associations between the accumulation of adversity (birth-63 years) and mental health (emotional symptom, life satisfaction, affective wellbeing) in older adults (63-69 years). Accumulation of adversity was assessed as the number of adversities and duration of exposure (number of lifecourse stages exposed to any, economic, psychosocial, or physical adversity). Linear regression tested their association with mental health, adjusted for sex, childhood cognition and emotional problems, and educational attainment.

RESULTS

Increased number of adversities was associated with increased emotional symptoms (β = 0.08 [0.06, 0.10]), decreased life satisfaction (β = -0.14 [-0.16, -0.12]) and decreased affective wellbeing (β = -0.08 [-0.10, -0.06]). Each additional duration of exposure was associated with a 0.38 [0.12, 0.65] standard deviation (SD) increase in emotional symptoms, and a - 0.68 [-0.96, -0.39] and -0.43 SD [-0.68, -0.18] decrease in life satisfaction and affective wellbeing, respectively. Life satisfaction showed stronger associations with economic and psychosocial compared to physical adversity.

LIMITATIONS

Some limitations include selective drop-out and lack of ethnic diversity.

CONCLUSIONS

Efforts to improve mental health in older adults should focus on reducing the number of adversities, as well as considering previous exposure across different lifecourse stages, to prevent adversities from becoming chronic. Future research should also consider the clustering and co-occurrence of different adversities across the lifecourse.

Occupational Mobility and Chronic Health Conditions in Middle and Later Life: A Systematic Review

BACKGROUND

Occupational mobility at various stages in the life course may have a cumulative impact on health outcomes and trajectory. This study aims to (1) systematically review empirical evidence regarding the impact of intergenerational and intra-generational occupational mobility on chronic health conditions in middle and later life; and (2) assess the collective evidence on the health consequences of different types of occupational mobility.

METHOD

A systematic review of literature was carried out by searching three databases (PubMed, PsycINFO, and SocINDEX) and the reference lists. Eligible studies examined the impact of occupational mobility on at least one chronic health condition among adults aged 35 years or above. The quality of each included study was assessed by standardized tools.

RESULTS

Out of 170 identified publications, 16 studies based on 12 independent data sets met the inclusion criteria. There is moderately strong evidence that downward intergenerational occupational mobility and stable low occupational status across generations were associated with worse chronic health conditions. The relationships to chronic health conditions were more pronounced for intergenerational occupational mobility than for intra-generational occupational mobility. Gender differences were observed in the relationship between occupational mobility and health.

CONCLUSION

Career advancement interventions should target both the career starters and older employees. More generous unemployment insurance systems are suggested in less egalitarian countries, especially during economic recession periods. Future studies of occupational mobility should give more attention to women and people from developing and Eastern countries.

Assessment of fetal pulmonary artery Doppler indices in pregnant women with rheumatoid arthritis and ankylosing spondylitis

PURPOSE

To investigate fetal pulmonary artery Doppler parameters in pregnant women with rheumatoid arthritis (RA) and ankylosing spondylitis (AS).

METHODS

This case-control study included 24 pregnant women diagnosed with 13 AS and 11 RA and 48 healthy pregnant women at 29-30 weeks of gestation. The demographic and clinical features were recorded, including disease type and duration, attacks during pregnancy, and medications. Pulmonary artery acceleration time (AT), ejection time (ET), and pulmonary artery acceleration time to ejection time (PATET) ratio were measured by manual trace with spectral Doppler ultrasound.

RESULTS

A shorter pulmonary AT and lower PATET ratio were found in the case group (34.8 ± 2.3, p < 0.001, 0.18 ± 0.02, p < 0.001, respectively). When comparing the groups that had an attack during pregnancy and had not, there were no significant differences in the pulmonary artery indices. We also demonstrated a moderate correlation between maternal disease years and the PATET ratio (r = -0.562, p = 0.004).

CONCLUSION

This is the first study to evaluate the effect of RA and AS on fetal pulmonary indices. Maternal inflammation might affect pulmonary development and circulation. Fetal pulmonary Doppler indices can be used to obtain further information about neonatal respiratory morbidities in rheumatological disorders.

'There and Back Again'-Forward Genetics and Reverse Phenotyping in Pulmonary Arterial Hypertension

Although the invention of right heart catheterisation in the 1950s enabled accurate clinical diagnosis of pulmonary arterial hypertension (PAH), it was not until 2000 when the landmark discovery of the causative role of bone morphogenetic protein receptor type II (BMPR2) mutations shed new light on the pathogenesis of PAH. Since then several genes have been discovered, which now account for around 25% of cases with the clinical diagnosis of idiopathic PAH. Despite the ongoing efforts, in the majority of patients the cause of the disease remains elusive, a phenomenon often referred to as "missing heritability". In this review, we discuss research approaches to uncover the genetic architecture of PAH starting with forward phenotyping, which in a research setting should focus on stable intermediate phenotypes, forward and reverse genetics, and finally reverse phenotyping. We then discuss potential sources of "missing heritability" and how functional genomics and multi-omics methods are employed to tackle this problem.

Respiratory Disease and Lower Pulmonary Function as Risk Factors for Dementia: A Systematic Review With Meta-analysis

BACKGROUND

In addition to affecting the oxygen supply to the brain, pulmonary function is a marker of multiple insults throughout life (including smoking, illness, and socioeconomic deprivation). In this meta-analysis of existing longitudinal studies, the hypothesis that lower pulmonary function and respiratory illness are linked to an elevated risk of dementia was tested.

METHODS

A systematic review was conducted of longitudinal studies using PubMed until April 1, 2019, and, where possible, results were pooled in random effects meta-analyses.

RESULTS

Ten studies relating pulmonary function to later dementia risk and 11 studies of respiratory illness and dementia (including one that assessed both factors) were identified. The lowest quartile of FEV₁ compared with the highest was associated with a 1.4-fold (hazard ratio [HR], 1.46; 95% CI, 0.77-2.75) increased dementia risk (N_total = 62,209; two studies). A decrease of 1 SD in FEV₁ was associated with a 28% increase in dementia risk (HR, 1.28; 95% CI, 1.03-1.60; N_total = 67,505; six studies). Respiratory illness was also associated with increased dementia risk to a similar degree (pooled HR, 1.54; 95% CI, 1.30-1.81; N_total = 288,641; 11 studies).

CONCLUSIONS

Individuals with poor pulmonary function experience an increased risk of dementia. The extent to which the association between poor pulmonary function and dementia is causal remains unclear and requires examination.

Pulmonary Consequences of Prenatal Inflammatory Exposures: Clinical Perspective and Review of Basic Immunological Mechanisms

Chorioamnionitis, a potentially serious inflammatory complication of pregnancy, is associated with the development of an inflammatory milieu within the amniotic fluid surrounding the developing fetus. When chorioamnionitis occurs, the fetal lung finds itself in the unique position of being constantly exposed to the consequent inflammatory meditators and/or microbial products found in the amniotic fluid. This exposure results in significant changes to the fetal lung, such as increased leukocyte infiltration, altered cytokine, and surfactant production, and diminished alveolarization. These alterations can have potentially lasting impacts on lung development and function. However, studies to date have only begun to elucidate the association between such inflammatory exposures and lifelong consequences such as lung dysfunction. In this review, we discuss the pathogenesis of and fetal immune response to chorioamnionitis, detail the consequences of chorioamnionitis exposure on the developing fetal lung, highlighting the various animal models that have contributed to our current understanding and discuss the importance of fetal exposures in regard to the development of chronic respiratory disease. Finally, we focus on the clinical, basic, and therapeutic challenges in fetal inflammatory injury to the lung, and propose next steps and future directions to improve our therapeutic understanding of this important perinatal stress.

Early Child Development, Residential Crowding, and Commute Time in 8 US States, 2010-2017

OBJECTIVES

To examine relationships of residential crowding and commute time with early child development.

METHODS

We used the Early Development Instrument (EDI), a teacher-reported, population-health measure of child development. The sample included child-level observations spanning 8 US states from 2010 to 2017 (n = 185 012), aggregated to the census tract (n= 2793), stratified by percentage of households in poverty. To test the association of commute times, crowding, and child development, we tested overall readiness and 5 EDI domains by using adjusted census tract-level multivariate regression with fixed effects.

RESULTS

In the full sample, a 1-standard-deviation increase in crowding was associated with 0.064- and 0.084-point decreases in mean score for cognitive development and communication skills, respectively. For the high-poverty subsample, a 1-standard deviation increase in commute time was associated with 0.081- and 0.066-point decreases in social competence and emotional maturity.

CONCLUSIONS

In neighborhoods with increased crowding or commute time, early child development suffers.

POLICY IMPLICATIONS

This study suggests a potential relationship between the changing urban landscape and child health. Children would benefit from more multisector collaboration between urban planning and public health.

Adult height and all-cause and cause-specific mortality in the Japan Public Health Center-based Prospective Study (JPHC)

Adult height is determined by both genetic characteristics and environmental factors in early life. Although previous studies have suggested that adult height is associated with risk of mortality, comprehensive associations between height and all-cause and cause-specific mortality in the Japanese population are unclear. We aimed to evaluate the associations between adult height and all-cause and cause-specific mortality among Japanese men and women in a prospective cohort study. We investigated 107,794 participants (50,755 men and 57,039 women) aged 40 to 69 years who responded to the baseline questionnaire in the Japan Public Health Center-based Prospective Study. Participants were classified by quartile of adult height obtained from a self-reported questionnaire in men (<160cm, 160-163cm, 164-167cm, ≥168cm) and women (<149cm, 149-151cm, 152-155cm, ≥156cm). Hazard ratios (HR) and 95% confidence intervals (CI) for mortality from all-cause, cancer, heart disease, cerebrovascular disease, respiratory disease, and other cause mortality were calculated using Cox proportional hazards models. During follow-up, 12,320 men and 7,030 women died. Taller adult height was associated with decreased risk for mortality from cerebrovascular disease (HR _{<160cm vs. ≥168cm} (95% CI) = 0.83 (0.69–0.99); HR _{for 5-cm increment} (95% CI) = 0.95 (0.90–0.99)) and respiratory disease (HR _{<160cm vs. ≥168cm} (95% CI) = 0.84 (0.69–1.03); HR _{for 5-cm increment} (95% CI) = 0.92 (0.87–0.97)), but was also associated with increased risk for overall cancer mortality (HR _{<160cm vs. ≥168cm} (95% CI) = 1.17 (1.07–1.28); HR _{for 5-cm increment} (95% CI) = 1.04 (1.01–1.07)) in men. Taller adult height was also associated with decreased risk for mortality from cerebrovascular disease (HR _{<149cm vs. ≥156cm} (95% CI) = 0.84 (0.66–1.05); HR _{for 5-cm increment} (95% CI) = 0.92 (0.86–0.99)) in women. Our results confirmed that adult height is associated with cause-specific mortality in a Japanese population.

Combined Impact of Smoking and Early-Life Exposures on Adult Lung Function Trajectories

RATIONALE

Both adverse early-life exposures and adult smoking can negatively influence adult lung function trajectory, but few studies consider how the impact of early-life exposures may be modified by subsequent smoking.

METHODS

The Medical Research Council National Survey of Health and Development is a nationally representative cohort, initially of 5,362 individuals, followed since enrollment at birth in March 1946. Using data collected prospectively across life and multilevel modeling, we investigated how the relationships between early-life exposures (infant lower respiratory infection, manual social class, home overcrowding, and pollution exposure) and FEV₁ and FVC trajectories between ages 43 and 60-64 years were influenced by smoking behavior.

MEASUREMENTS AND MAIN RESULTS

Among 2,172 individuals, there were synergistic interactions of smoking with infant respiratory infection (P = 0.04) and early-life home overcrowding (P = 0.009), for FEV₁ at 43 years. Within smoker-stratified models, there were FEV₁ deficits among ever-smokers associated with infant lower respiratory infection (-108.2 ml; P = 0.001) and home overcrowding (-89.2 ml; P = 0.002), which were not evident among never-smokers (-15.9 ml; P = 0.69 and -13.7 ml; P = 0.70, respectively). FVC modeling, including 1,960 individuals, yielded similar results. FEV₁ decline was greater in smokers (P < 0.001), but there was no effect of any early-life exposure on FEV₁ decline. Neither smoking nor early-life exposures were associated with FVC decline.

CONCLUSIONS

Besides accelerating adult FEV₁ decline, cigarette smoking also modifies how early-life exposures impact on both midlife FEV₁ and FVC. These findings are consistent with smoking impairing pulmonary development during adolescence or early adulthood, thereby preventing catch-up from earlier acquired deficits.

Childhood conscientiousness predicts the social gradient of smoking in adulthood: a life course analysis

BACKGROUND AND AIMS

The social gradient in smoking is well known, with higher rates among those in less advantaged socioeconomic position. Some recent research has reported that personality characteristics partly explain this gradient. However, the majority of existing work is limited by cross-sectional designs unsuitable to determine whether differences in conscientiousness are a predictor or a product of social inequalities. Adopting a life course perspective, we investigated in the current paper the influence of conscientiousness in early and mid-life on the social gradient in smoking and the role of potential confounding factors in a large longitudinal cohort study.

METHODS

Using data from the 1958 National Child Development Study, we examined the extent to which two measures of conscientiousness, one assessed with a personality questionnaire at age 50 and one derived from three related items at 16 years in childhood, explained the social gradient of smoking at age 50 by comparing nested logistic regression models that included social class at birth, cognitive ability, attention and conduct problems at age 7, and educational qualification.

RESULTS

Childhood conscientiousness was a significant predictor of smoking at 50 years (OR=0.86, CI (95%) 0.84 to 0.88), explaining 5.0% of the social gradient independent of all other variables. Childhood conscientiousness was a stronger predictor than adult conscientiousness, statistically accounting for the observed direct association of adult conscientiousness with smoking.

CONCLUSIONS

Conscientiousness may be a predictor rather than a product of social differences in smoking. Inclusion of personality measures and adoption of a life course perspective add significantly to our understanding of health inequalities.

The Psychology of Home Environments

Homes are important: People devote much of their thought, time, and resources to selecting, modifying, and decorating their living spaces, and they may be devastated when their homes must be sold or are destroyed. Yet the empirical psychological literature says virtually nothing about the roles that homes might play in people’s lives. We argue that homes provide an informative context for a wide variety of studies examining how social, developmental, cognitive, and other psychological processes play out in a consequential real-world setting. The topic of homes is also well suited to collaborations with a diverse array of disciplines ranging from architecture and engineering to sociology and law. We illustrate the potential insights to be gained from studying homes with an exploratory study that maps the psychological ambiances (e.g., romance, comfort, togetherness) that people desire in their homes; we identify six broad ambiance dimensions (restoration, kinship, storage, stimulation, intimacy, productivity) that show mean differences across rooms. We connect these findings to existing work on situation selection in emotion regulation. These ideas provide only an initial foray into the domain of residential space, but they hint at the productive roles that homes and other spaces could play in psychological theorizing and research.

Cross-sectional associations between air pollution and chronic bronchitis: an ESCAPE meta-analysis across five cohorts

BACKGROUND

This study aimed to assess associations of outdoor air pollution on prevalence of chronic bronchitis symptoms in adults in five cohort studies (Asthma-E3N, ECRHS, NSHD, SALIA, SAPALDIA) participating in the European Study of Cohorts for Air Pollution Effects (ESCAPE) project.

METHODS

Annual average particulate matter (PM(10), PM(2.5), PM(absorbance), PM(coarse)), NO(2), nitrogen oxides (NO(x)) and road traffic measures modelled from ESCAPE measurement campaigns 2008-2011 were assigned to home address at most recent assessments (1998-2011). Symptoms examined were chronic bronchitis (cough and phlegm for ≥3 months of the year for ≥2 years), chronic cough (with/without phlegm) and chronic phlegm (with/without cough). Cohort-specific cross-sectional multivariable logistic regression analyses were conducted using common confounder sets (age, sex, smoking, interview season, education), followed by meta-analysis.

RESULTS

15 279 and 10 537 participants respectively were included in the main NO(2) and PM analyses at assessments in 1998-2011. Overall, there were no statistically significant associations with any air pollutant or traffic exposure. Sensitivity analyses including in asthmatics only, females only or using back-extrapolated NO(2) and PM10 for assessments in 1985-2002 (ECRHS, NSHD, SALIA, SAPALDIA) did not alter conclusions. In never-smokers, all associations were positive, but reached statistical significance only for chronic phlegm with PM(coarse) OR 1.31 (1.05 to 1.64) per 5 µg/m(3) increase and PM(10) with similar effect size. Sensitivity analyses of older cohorts showed increased risk of chronic cough with PM(2.5abs) (black carbon) exposures.

CONCLUSIONS

Results do not show consistent associations between chronic bronchitis symptoms and current traffic-related air pollution in adult European populations.

MUC5AC and inflammatory mediators associated with respiratory outcomes in the British 1946 birth cohort

Background and objective: Dysregulation of respiratory mucins, MUC5AC in particular, has been implicated in respiratory disease and MUC5AC expression is up-regulated in response to environmental challenges and inflammatory mediators. The aim of this study was to examine the effect of genetic variation on susceptibility to common respiratory conditions.

Methods: The association of MUC5AC and the closely linked genes MUC2 and MUC5B with respiratory outcomes was tested in the MRC National Survey of Health and Development, a longitudinal birth cohort of men and women born in 1946. Also examined were the functional variants of the genes encoding inflammatory mediators, IL13, IL1B, IL1RN, TNFA and ERBB1, for which there is a likely influence on MUC5AC expression and were explored potential gene-gene interactions with these inflammatory mediators.

Results: Statistically significant associations between the 3'ter MUC5AC simple nucleotide polymorphism (SNP) rs1132440 and various non-independent respiratory outcomes (bronchitis, wheeze, asthma, hay fever) were reported while the adjacent loci show slight (but largely non-statistically significant) differences, presumably reflective of linkage disequilibrium (allelic association) across the region. A novel association between bronchitis and a non-synonymous functional ERBB1 SNP, rs2227983 (aka epidermal growth factor receptor:R497K, R521K) is also reported and evidence presented of interaction between MUC5AC and ERBB1 and between MUC5AC and IL1RN with respect to bronchitis. The ERBB1 result suggests a clear mechanism for a biological interaction in which the allelic variants of epidermal growth factor receptor differentially affect mucin expression.

Conclusions: The MUC5AC association and the interactions with inflammatory mediators suggest that genetically determined differences in MUC5AC expression alter susceptibility to respiratory disease.

SUMMARY AT A GLANCE

This longitudinal cohort study shows occurrence of the common respiratory conditions bronchitis, wheeze, asthma and hay fever to be associated with genetic variation in a mucin gene, MUC5AC. Functional variation in the epidermal growth factor receptor (epidermal growth factor receptor encoded by ERBB1) is also associated with bronchitis and modulates the MUC5AC effect.

Critical role of smoking and household dampness during childhood for adult phlegm and cough: a research example from a prospective cohort study in Great Britain

OBJECTIVE

To examine independent associations between childhood exposures to smoking and household dampness, and phlegm and cough in adulthood.

DESIGN

A prospective cohort study.

PARTICIPANTS

7320 of the British cohort who were born during 1 week in 1970 and had complete data for childhood and adult information.

MAIN OUTCOME MEASURES

Experiences of phlegm and coughing over the previous 3 months were assessed using questions from the Medical Research Council (MRC) Questionnaire on respiratory symptoms when the cohort participants were 29 years of age. 4 response patterns (no symptoms, phlegm only, cough only, both symptoms present) were created based on the responses to these questions.

RESULTS

Childhood smoking and exposure to marked household dampness at age 10 were associated with phlegm (childhood smoking: relative risk ratio (RRR)=1.45, 95% CI 1.02 to 2.05; dampness: RRR=2.05, 95% CI 1.07 to 3.91) and co-occurring cough and phlegm (childhood smoking: RRR=1.35. 95% CI 1.08 to 1.67; dampness: RRR=2.73, 95% CI 1.88 to 3.99), while exposure to two or more adult smokers in the household was associated with cough-related symptoms (cough only: RRR=1.28, 95% CI 1.04 to 1.58; phlegm and cough: RRR=1.32, 95% CI 1.06 to 1.64). These associations were independent from adult smoking, childhood phlegm and cough, early social background and sex. Current smoking at age 29 contributed to all symptom patterns; however, a substantial association between household dampness and co-occurring phlegm and cough suggest long-term detrimental effects of childhood environmental exposures.

CONCLUSIONS

Our findings give support to current public health interventions for adult smoking and raise concerns about the long-term effects of a damp home environment on the respiratory health of children.

Association of socioeconomic position with smoking and mortality: the contribution of early life circumstances in the 1946 birth cohort

BACKGROUND

A large part of the socioeconomic mortality gradient can be statistically accounted for by social patterning of adult health behaviours. However, this statistical explanation does not consider the early life origins of unhealthy behaviours and increased mortality risk.

METHODS

Analysis is based on 2132 members of the MRC National Survey of Health and Development with mortality follow-up and complete data. Smoking behaviour was summarised by pack-years of exposure. Socioeconomic circumstances were measured in childhood (father's social class (age 4), maternal education (age 6)) and age 26 (education attainment, home ownership, head of household social class). We estimated the direct effect of early circumstances, the indirect effect through smoking and the independent direct effect of smoking on inequality in all-cause mortality from age 26 to 66.

RESULTS

Mortality risk was higher in those with lower socioeconomic position at age 26, with a sex-adjusted HR (relative index of inequality) of 1.97 (95% CI 1.18 to 3.28). Smoking and early life socioeconomic indicators together explained 74% of the socioeconomic gradient in mortality (the gradient). Early life circumstances explained 47% of the gradient, 23.5% directly and 23.0% indirectly through smoking. The explanatory power of smoking behaviour for the gradient was reduced from 50.8% to 28% when early life circumstances were added to the model.

CONCLUSIONS

Early life socioeconomic circumstances contributed importantly to social inequality in adult mortality. Our life-course model focusing on smoking provides evidence that social inequalities in health will persist unless prevention strategies tackle the intergenerational transmission of disadvantage and risk.

Spatial variation in the risk of hospitalization with childhood pneumonia and empyema in the North of England

The aim of this study was to investigate spatial variation in risk of hospitalization in childhood pneumonia and empyema in the North of England and associated risk factors. Data on childhood (0-14 years) hospital admissions with a diagnosis pneumonia or empyema were linked to postcode districts. Bayesian conditional autoregressive models were used to evaluate spatial variation and the relevance of specific spatial covariates in an area-based study using postcode as the areal unit. There was a sixfold variation in the risk of hospitalization due to pneumonia across the study region. Variation in risk was associated with material deprivation, Child Well-being Index (CWI) health domain score, number of children requiring local authority support, and distance to hospital. No significant spatial variation in risk for empyema was found.

Economic stress in childhood and adulthood, and self-rated health: a population based study concerning risk accumulation, critical period and social mobility

BACKGROUND

Research in recent decades increasingly indicates the importance of conditions in early life for health in adulthood. Only few studies have investigated socioeconomic conditions in both childhood and adulthood in relation to health testing the risk accumulation, critical period, and social mobility hypotheses within the same setting. This study investigates the associations between economic stress in childhood and adulthood, and self-rated health with reference to the accumulation, critical period and social mobility hypotheses in life course epidemiology, taking demographic, social support, trust and lifestyle factors into account.

METHODS

The public health survey in Skåne (southern Sweden) in 2008 is a cross-sectional postal questionnaire study based on a random sample, in which 28,198 persons aged 18-80 years participated (55% participation). Logistic regression models were used to investigate associations between economic stress in childhood and adulthood, and self-rated health.

RESULTS

Three life-course socioeconomic models concerning the association between economic stress and self-rated health (SRH) were investigated. The results showed a graded association between the combined effect of childhood and adulthood economic stress and poor SRH in accordance with the accumulation hypothesis. Furthermore, upward social mobility showed a protecting effect and downward mobility increased odds ratios of poor SRH in accordance with the social mobility hypothesis. High/severe economic stress exposures in both stages of life were independently associated with poor SRH in adulthood. Furthermore, stratifying the study population into six age groups showed similar odds ratios of poor SRH regarding economic stress exposure in childhood and adulthood in all age groups among both men and women.

CONCLUSIONS

The accumulation and social mobility hypotheses were confirmed. The critical period model was confirmed in the sense that both economic stress in childhood and adulthood had independent effects on poor SRH. However, it was not confirmed in the sense that a particular window in time (in childhood or adulthood) had a specifically high impact on self-rated health.

The association between food insecurity and inflammation in the US adult population

OBJECTIVES

To expand the understanding of potential pathways through which food insecurity is associated with adverse health outcomes, we investigated whether food insecurity is associated with nutritional levels, inflammatory response, and altered immune function.

METHODS

We performed a cross-sectional analysis of the National Health and Nutrition Examination Survey (1999-2006) with 12,191 participants. We assessed food insecurity using the US Department of Agriculture food security scale module and measured clinical biomarkers from blood samples obtained during participants' visits to mobile examination centers.

RESULTS

Of the study population, 21.5% was food insecure. Food insecurity was associated with higher levels of C-reactive protein (adjusted odds ratio [AOR]=1.21; 95% confidence interval [CI]=1.04, 1.40) and of white blood cell count (AOR=1.36; 95% CI=1.11, 1.67). White blood cell count partly mediated the association between food insecurity and C-reactive protein.

CONCLUSIONS

These findings show that food insecurity is associated with increased inflammation, a correlate of chronic diseases. Immune response also appears to be a potential mediator in this pathway.

Early life financial adversity and respiratory function in midlife: a prospective birth cohort study

Data from the 1958 National Child Development Study (1958-2004) were used in a prospective study of the relation of financial adversity in childhood to lung function in midlife. It was hypothesized that such a relation would be found and would be mediated partly by early housing deprivation, partly by continuities in social disadvantage, and partly by smoking. These hypotheses were confirmed. The mediating variables explained nearly two-thirds of the observed relation. The strongest individual pathway from early financial hardship to adult lung function was through poor housing in childhood. Poor housing increased the risk of educational failure, which in turn was strongly related to less-advantaged social class. Lack of educational qualifications and less-advantaged social class independently increased the risk of higher levels of smoking. Mediating variables therefore acted in part as indicators of environmental exposures and in part through their links to adult smoking. Early financial adversity is associated with adult lung function partly through poor housing and partly through pathways involving continuities in social disadvantage and the associated environmental exposures and behaviors.

A life course approach: research orientations and future challenges

The need to study lifelong changes in health and functioning has resulted in increasing emphasis on a life course approach in different fields of inquiry. The aim of this approach is to explore how biological, psychological, and social risk factor trajectories, acting across the entire life course, influence age-related diseases, functional decline, and disability. The importance of the first years of life upon later development and adult characteristics was generally recognized already in the first half of the twentieth century, but it was not until the 1990s that different strands of medical and social research converge in the field of life course epidemiology, in which epidemiological processes are approached using different models such as biological programming, critical periods, pathways, and accumulation. The biological programming model holds that organ development in utero and early infancy determines the maximum functional capacity that an individual can attain and influences the development of certain chronic diseases later in life. The critical period model extends the idea to include child development and key social transitions over the entire life course. The pathway model focuses on the cumulative effect of life events along the developmental trajectories, with early advantage or disadvantage setting a person on a pathway to a later etiologically important exposure. The accumulation model describes the underlying social, behavioral, and biological processes that drive the impact of the life course on health. The growing focus on life course determinants of aging also has implications for studies of long-term changes in physical activity and their role in determining both gains and losses of health and functioning with aging. A life course approach presents great challenges for the continued development of testable theoretical models and effective study design and analysis.

Characterisation of smoking behaviour across the life course and its impact on decline in lung function and all-cause mortality: evidence from a British birth cohort

OBJECTIVES

To describe smoking trajectories from early adolescence into mid-life and to examine the effects of these trajectories on health and all-cause mortality.

METHODS

A nationally representative birth cohort study including 3387 men and women followed up since their birth in 1946 in England, Scotland and Wales. The main outcome measure is all-cause mortality by age 60 years and rate of decline in forced expiratory volume in 1 second (FEV(1)).

RESULTS

Eighteen per cent of the sample were categorised as lifelong smokers (smokers at all six waves at ages 20, 25, 31, 36, 43, 53 years), of whom 90% had begun smoking by age 18 years. By age 60 years, 10% of all lifelong smokers had died. They had a threefold increase in mortality rate compared with never smokers (hazard ratio (HR) 3.2, 95% confidence interval (CI) 2.1 to 4.8). For predominantly smokers (smokers for at least four of the six data collections), mortality rate remained higher than never smokers (HR 1.6, 95% CI 1.0 to 2.5). Predominantly non-smokers did not differ from those who never smoked (HR 1.3, 95% CI 0.9 to 2.0). Using the most recent smoking status available, current smokers had more than double the risk of mortality compared with never smokers (HR 2.4, 95% CI 1.6 to 3.5). Lifelong smokers and predominantly smokers had a greater rate of decline in lung function than never smokers (regression coefficients -18 ml/year, 95% CI -22 to -13; -6, 95% CI -10.3 to -1.7 respectively). For current smokers, the decline was 8.4 ml/year (95% CI -12.0 to -5.0) faster than never smokers.

CONCLUSIONS

The strength and differentiation of adverse effects identified by using simplified smoking behaviours has highlighted the advantages of obtaining further information on lifelong smoking behaviour from former smokers, rather than just current smoking status.

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.

Life-course approaches to inequalities in adult chronic disease risk

A life-course approach to chronic-disease epidemiology uses a multidisciplinary framework to understand the importance of time and timing in associations between exposures and outcomes at the individual and population levels. Such an approach to chronic diseases is enriched by specification of the particular manner in which timing in relation to physical growth, reproduction, infection, social mobility, behavioural transitions etc. can influence various adult chronic diseases in different ways, and more ambitiously by how these temporal processes are interconnected and manifested in health inequalities within a population and in population-level disease trends. The paper will discuss some historical background to life-course epidemiology and theoretical models of life-course processes, and will review some of the empirical evidence linking life-course processes to CHD, haemorrhagic stroke, stomach cancer and other chronic diseases in adulthood. It will also underscore that a life-course approach offers a way to conceptualize how underlying socio-environmental determinants of health, experienced at different life-course stages, can differentially influence the development of chronic diseases, as mediated through proximal specific biological processes.

Public housing, health and health behaviors: is there a connection?

This paper explores the relationship between public housing, health outcomes, and health behaviors among low-income housing residents. While public housing can be a dangerous and unhealthy environment in which to live, the subsidized rent may free up resources for nutritious food and health care. In addition, public housing may be of higher quality than the available alternatives, it may provide easier access to health clinics willing to serve the poor, and it may link residents to social support networks, which can improve mental health and the ability to access higher-quality grocery stores. To test whether there is a "back-door" health benefit to the public housing program, we analyze data from the Fragile Families and Child Wellbeing Study. We minimize the effects of selection into public housing with controls and instrumental variables estimation and find that the results are somewhat sensitive to the instrumental variable used, and thus, we conclude that we are unable to detect a robust health benefit from public housing for our measures of health. However, we do find some evidence that public housing residency has mixed effects on domestic violence, increases obesity, and worsens mothers' overall health status.

Elevated exhaled nitric oxide in newborns of atopic mothers precedes respiratory symptoms

RATIONALE

Exhaled nitric oxide (NO) is a well-known marker of established airway inflammation in asthma. Its role in the disease process before the onset of respiratory symptoms remains unclear.

OBJECTIVES

To examine whether elevated NO in newborns with clinically naive airways is associated with subsequent respiratory symptoms in infancy.

METHODS

We measured exhaled NO concentration and output after birth and prospectively assessed respiratory symptoms during infancy in a birth cohort of 164 unselected healthy neonates. We examined a possible association between NO and respiratory symptoms using Poisson regression analysis.

RESULTS

In infants of atopic mothers, elevated NO levels after birth were associated with increased risk of subsequent respiratory symptoms (risk ratio [RR], 7.5; 95% confidence interval [CI], 1.7-32.4 for each nl/s increase in NO output; p = 0.007). Similarly, a positive association between NO and symptoms was seen in infants of smoking mothers (RR, 6.6; 95% CI, 2.3-19.3; p = 0.001), with the strongest association in infants whose mothers had both risk factors (RR, 21.8; 95% CI, 5.8-81.3; p < 0.001).

CONCLUSIONS

The interaction of NO with maternal atopy and smoking on subsequent respiratory symptoms is present early in life. Clinically, noninvasive NO measurements in newborns may prove useful as a new means to identify high-risk infants. Future confirmation of a role for NO metabolism in the evolution of respiratory disease may provide an avenue for preventative strategies.

MUC7 haplotype analysis: results from a longitudinal birth cohort support protective effect of the MUC7*5 allele on respiratory function

The mucin MUC7 is a glycoprotein that plays a role in bacterial clearance and has candidacidal activity. There are two common allelic forms with 5 or 6 tandem repeats (TR) of a 23 amino acid motif within the highly glycosylated (mucin) domain. The MUC7*5 allele has previously been shown to be less prevalent in patients with asthma, suggesting a protective role in respiratory function. Here we report the characterisation of other frequent genetic variation within and in the vicinity of the gene MUC7. A total of 26 polymorphisms were identified of which 5 are located in transcribed regions. A subset of 8 polymorphisms was selected to represent the major haplotypes, and allelic association was studied in individuals of Northern European ancestry, including known asthmatics. There was low haplotype diversity and strong association between each of the loci, and the MUC7*5 allele-carrying haplotype remained the one most strongly associated with asthma. Five of these polymorphisms have also been tested in the 1946 longitudinal birth cohort, for whom developmental, environmental and respiratory health data are available. We show that the haplotype carrying MUC7*5 is associated with higher FEV1 at 53 years, reduced age-related decline of FEV1, and also reduced incidence of wheeze.

Lung function and cognitive ability in a longitudinal birth cohort study

OBJECTIVE

The objective of this study was to examine the association between forced expiratory volume in 1 second (FEV1) and cognitive ability in midlife in the normal population.

METHODS

Multiple regression was used to test associations between FEV1 and cognitive function in 1778 men and women in the MRC National Survey of Health and Development, also known as the British 1946 birth cohort. Analyses were adjusted for sex, body size (birth weight, adult height, weight, and chest circumference), socioeconomic status, lifetime smoking, and a range of health indicators, including early respiratory vulnerability (infant lower respiratory infection, childhood asthma, and exposure to atmospheric pollution).

RESULTS

FEV1 at 43 years was associated with slower psychomotor speed (peg placement) at the same age and with slower decline in psychomotor speed (letter search speed) from 43 to 53 years, independently of the previously mentioned potential confounders. These independent associations were not observed, however, for adult verbal ability, verbal memory, or rate of decline in memory, which were significantly explained by socioeconomic status and adolescent cognitive ability. In a subsequent analysis, adolescent cognition was positively associated with FEV1, although not with rate of decline in FEV1 from 43 to 53 years, again independently of the previously mentioned confounders.

CONCLUSIONS

Cognitive function and FEV1 are positively associated across the life course. One possible explanation lies in the parallel action of endocrine, autonomic, and motor control systems on respiration and higher mental function. Because respiration and mental function are both associated with functional capacity and survival, this is a matter of potential clinical significance.

A life course approach to chronic disease epidemiology

A life course approach to chronic disease epidemiology uses a multidisciplinary framework to understand the importance of time and timing in associations between exposures and outcomes at the individual and population levels. Such an approach to chronic diseases is enriched by specification of the particular way that time and timing in relation to physical growth, reproduction, infection, social mobility, and behavioral transitions, etc., influence various adult chronic diseases in different ways, and more ambitiously, by how these temporal processes are interconnected and manifested in population-level disease trends. In this review, we discuss some historical background to life course epidemiology and theoretical models of life course processes, and we review some of the empirical evidence linking life course processes to coronary heart disease, hemorrhagic stroke, type II diabetes, breast cancer, and chronic obstructive pulmonary disease. We also underscore that a life course approach offers a way to conceptualize how underlying socio-environmental determinants of health, experienced at different life course stages, can differentially influence the development of chronic diseases, as mediated through proximal specific biological processes.

Alpha1-Antitrypsin as a Risk for Infant and Adult Respiratory Outcomes in a National Birth Cohort

Reduced alpha1-antitrypsin (AAT) encoded by the gene SERPINA1 is a potential risk for pulmonary disease. We investigated SERPINA1 polymorphism as a risk for infant and adult pulmonary morbidity, and adult respiratory function and its change between 43 and 53 yr. We used data on a British national representative sample (n = 5,362) studied since birth in 1946 to age 53 yr (when n = 3,035), when DNA was first obtained. SERPINA1 Z and, to a lesser extent, S carriers had an increased risk of infant lower respiratory infection compared with those who were neither S nor Z carriers (Z carriers: odds ratio = 2.32, 95% confidence interval = 1.37-3.92; S but not Z carriers odds ratio = 1.58, 95% confidence interval = 1.10-2.28) after adjustment for environmental, socioeconomic, and developmental factors, and breast-feeding. There was no difference in the adult outcomes at 53 yr according to genotype, nor was there any association of genotype with change in forced expiratory volume at 1 s between 43 and 53 yr. Lower alpha1-antitrypsin, as indicated by carrier status for the Z and S alleles, was a risk for infant lower respiratory infection, but not for adult respiratory outcomes.

Can we disentangle life course processes of accumulation, critical period and social mobility? An analysis of disadvantaged socio-economic positions and myocardial infarction in the Stockholm Heart Epidemiology Program

The accumulation hypothesis would propose that the longer the duration of exposure to disadvantaged socio-economic position, the greater the risk of myocardial infarction. However there may be a danger of confounding between accumulation and possibly more complex combinations of critical periods of exposure and social mobility. The objective of this paper is to investigate the possibility of distinguishing between these alternatives. We used a population based case-control study (Stockholm Heart Epidemiology Programme) of all incident first events of myocardial infarction among men and women, living in the Stockholm region 1992-94. The analyses were restricted to men 53-70 years, 511 cases and 716 controls. From a full occupational history each subject was categorized as manual worker or non-manual at three stages of the life course, childhood (from parent's occupation), at the ages 25-29 and 51-55, resulting in 8 possible socio-economic trajectories. We found a graded response to the accumulation of disadvantaged socio-economic positions over the life course. However, we also found evidence for effects of critical periods and of social mobility. A conceptual analysis showed that there are, for theoretical reasons, only a limited number of trajectories available, too small to form distinct empirical categories of each hypothesis. The empirical task of disentangling the life course hypotheses of critical period, social mobility and accumulation is therefore comparable to the problem of separating age, period, and cohort effects. Accordingly, the interpretation must depend on prior knowledge of more specific causal mechanisms.

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.

Social deprivation and hospital admission for respiratory infection: an ecological study

STUDY OBJECTIVE

To examine the relationship between social deprivation and risk of hospital admission for respiratory infection.

METHODS AND SUBJECTS

Ecological study using hospital episode statistics and population census data. Cases were residents of the West Midlands Health Region admitted to hospital with a diagnosis of respiratory infection, acute respiratory infection, pneumonia or influenza over a 5-year period. Postcodes of cases were used to assign Townsend deprivation scores; these were then ranked and divided into five deprivation categories. Poisson regression analysis was used to estimate the magnitude of effect for associations between deprivation category and hospital admission by age and admitting diagnosis.

MAIN RESULTS

There were 136755 admissions for respiratory infection, equivalent to an annual admission rate of 27.1 per 1000 population (95% CI = 26.9-27.2). Deprivation was associated with increased admission rates for all respiratory infection (P < 0.0001) and affected all age-groups. The greatest effect was in the 0-4 years age-group with admission rates 91% higher in the most deprived children compared to the least deprived. Hospital admissions for acute respiratory infection and pneumonia were both significantly associated with deprivation (P < 0.0001).

CONCLUSIONS

Respiratory infection is associated with social inequalities in all age-groups, particularly in children. Prevention of respiratory infection could make an important contribution to reducing health inequalities.

The life course prospective design: an example of benefits and problems associated with study longevity

Although the life course prospective study design has many benefits, and information from such studies is in increasing demand for scientific and policy purposes, it has potential inherent design problems associated with its longevity. These are in particular the fixed sample structure and the data collected in early life, which are each determined by the scientific principles of another time and the risk over time of increased sample loss and distortion through loss. The example of a national birth cohort in Britain, studied from birth so far to age 53 years is used to address these questions. Although the response rate is high, avoidable loss, which was low in childhood, increased in adulthood, and was highest in those in adverse socio-economic circumstances and those with low scores on childhood cognitive measures. Recent permanent refusal rate rises may be the result of better tracing and/or a response to increased requests for biological measurement. Nevertheless, the responding sample continues in most respects to be representative of the national population of a similar age. Consistency of response over the study's 20 data collections has been high. The size of the sample responding in adulthood is adequate for the study of the major costly diseases, and for the study of functional ageing and its precursors. This study's continuation has depended not only on scientific value but also policy relevance. Although the problems inherent in the prospective design are unavoidable they are not, in the study described, a barrier to scientific and policy value. That seems also likely in Britain's two later born national birth cohort studies that have continued into adulthood.

[Socioeconomic circumstances and premature mortality from chronic diseases]

BACKGROUND AND OBJECTIVE

Our aim was to investigate the association between socioeconomic factors in childhood or adolescence and adulthood and premature mortality from various causes of death.

SUBJECTS AND METHOD

Men and women aged 25-74 years residing on May 1, 1996, in the Autonomous Community of Madrid. For the next 19 months, information on individuals who died and the cause of death were obtained from the Mortality Register. We estimated the mortality from 5 types of cancer and from 4 chronic diseases by the educational level--as an indicator of the socioeconomic circumstances in childhood or adolescence--and by income--as an indicator of the socioeconomic circumstances in adulthood.

RESULTS

When both variables were included in the analysis simultaneously, the relative mortality ratio for men with second grade first phase and lower educational level versus those with second grade, second phase and higher educational level and the relative mortality ratio for men belonging to income quartiles 3 and 4 (lowest) versus those belonging to quartiles 1 and 2 were, respectively: 1.15 (95% confidence interval 1.01-1.31) and 1.22 (1.09-1.36) for lung cancer; 1.46 (1.19-1,93) and 1.13 (0.90-1.41) for gastric cancer; 1.80 (1.32-2.44) and 1.46 (1.18-1.80) for chronic obstructive pulmonary disease; and 1.18 (0.77-1.81) and 0.68 (0.47-0.98) for diabetes mellitus. For women the relative mortality ratios were, respectively: 0.63 (0.43-0.92) and 0.72 (0.52-0.99) for lung cancer; 1.68 (0.99-2.83) and 1.17 (0.86-1.60) for gastric cancer; 0.76 (0.61-0.94) and 0.98 (0.82-1.16) for breast cancer; 1.36 (0.95-1.95) and 1.20 (0.97-1.48) for ischemic heart disease; 1.72 (1.19-2.50) and 0.93 (0.75-1.16) for stroke; and 2.23 (0.94-5.27) and 1.51 (1.02-2.25) for diabetes mellitus.

CONCLUSIONS

Premature mortality in adulthood is associated with several socioeconomic factors acting across the whole course of life. The contribution of these socioeconomic circumstances to mortality varies regarding the cause of death and gender.

Obesity and asthma: evidence for and against a causal relation

The evidence for an association between asthma and obesity in adults, and in children and adolescents, is reviewed. Few studies in adults measured height and weight, whereas the majority in children did. Evidence for the association is strong, but that for a gender interaction is weak. There is sufficient evidence to rule out asthma preceding obesity as an explanation, and that increased perception of symptoms in the obese, or a purely mechanical effect, is responsible. However, direct causality is unlikely, because in children the association is of recent origin, and trends in obesity do not explain the rising prevalence of asthma. Atopy was not associated with obesity in a large adult study. Potential explanations that require further investigation are that gastroesophageal reflux as a result of obesity causes asthma, that physical inactivity may promote both obesity and asthma, and that the diets of obese subjects may potentiate asthma.

The use of quantitative medical sociology

The present article reviews, in relation to quantitative work on the social structure, papers published in Sociology of Health and Illness during its first 25 years. Each issue published during the years 1979-2002 has been examined; and quantitative papers, relating to various aspects of the social structure, have been identified. Such papers are found to have formed a minor but substantively significant theme within the Journal. These contributions situate the journal between sociology and social epidemiology. Articles in the Journal, for example, have been part of sociological debates about the measurement of social class, and of social epidemiological debates about the relationship between income distribution and population health. The contribution of Sociology of Health and Illness to a number of such debates is reviewed. The article concludes that the present situation, in particular the intellectual crisis in social epidemiology and social science investment in large data sets, gives the Journal the chance to build on this distinguished tradition by encouraging, through its publication policy, the further development of quantitative medical sociology.

Building an inter-disciplinary science of health inequalities: the example of lifecourse research

Across the post-industrial world, new public health strategies are being developed with the goal of reducing the socio-economic gradient in health. These new strategies are distinguished by a commitment to tackling the macro determinants of health inequalities through policies informed by scientific evidence. The engagement with macro determinants and with scientific evidence presents a major challenge to the health inequality research community. This is not only because of the complexity of the links between distal causes, proximal risk factors and health outcomes. It is also and more importantly because of the narrow disciplinary base of health inequality research. Grounded in social epidemiology, health inequality research has illuminated the pathways which run from individual socio-economic position to health-but has left in shadow the factors which influence socio-economic position. Broadening the evidence base to include these structural processes requires a new science of health inequalities, resourced both by epidemiological research and by research on social inequality and social exclusion. The paper demonstrates how such an inter-disciplinary science can be constructed. Taking lifecourse research as its example and the UK as its case study, it nests epidemiological research within social policy research: setting evidence on the health consequences of cumulative exposures within research on lifecourse dynamics, and locating both within analyses of how state policies can amplify or moderate inequalities in socio-economic position.

Multiple measures of socio-economic position and psychosocial health: proximal and distal measures

BACKGROUND

The aim of this paper is to compare three models for exploring the links between different measures of adult socioeconomic position (SEP)-education, occupation, income-and psychosocial health. Model I is a basic univariate regression model with psychosocial health as the outcome and a measure of SEP as the predictor. Model II is a multiple regression model with psychosocial health as the outcome with all three measures of SEP allocated the same temporal position as predictors. Model III treats education, a distal measure of SEP, as antecedent to the proximal measures of SEP in the prediction equations linking SEP to health.

METHODS

Participants were drawn from the Whitehall II study, a prospective cohort study of British civil servants. Data analysed here are from Phase 5 (1997-1999) of data collection, 7830 individuals in all. The measures of SEP and psychosocial health were assessed via a self-administered questionnaire.

RESULTS

The three models can lead to completely different conclusions. Model III, our preferred model, shows education to have a stronger indirect effect on psychosocial health when compared to its direct effect. The indirect effect is due to the effect of education on proximal measures of social position, occupation, and income in this case.

CONCLUSIONS

Results reported here support the hypothesis that a comparison of the relative importance of the different measures of social position in predicting health is meaningless if the causal relationships among these measures are not accounted for.

Sociodemographic inequalities in the diet of young children in the 1946 British birth cohort

OBJECTIVE

To evaluate whether there was food and nutrient equality across occupational social classes and geographical region for members of the 1946 British birth cohort at age 4 years.

DESIGN

Cross-sectional analysis of selected food groups, energy and nutrients from one-day recall diet records.

SETTING

England, Scotland and Wales in 1950.

SUBJECTS

Nationally representative sample of 4419 children aged 4 years in 1950 from the MRC National Survey of Health and Development (NSHD) (1946 Birth Cohort).

RESULTS

Significant food and nutrient inequalities occurred by region and occupational social class of the father. Disparity in fruit and vegetable consumption primarily led to the nutrient differences, especially with respect to lower vitamin C and carotene intakes in children from Scotland and from a manual social class background. Lower energy intake in Scottish children was attributable to inequality in the consumption of foods providing fat, and also to the retention of the traditional Scottish diet that included porridge and soups. Consumption of some rationed foods -- bacon, orange juice and tea -- was inequitably distributed by father's social class, but others, in particular meat and spreading fats, were consumed more uniformly. In contrast to fruits and vegetables, which showed marked sociodemographic disparities, other non-rationed foods such as bread and potatoes were consumed universally.

CONCLUSION

Local cultural norms may have played as strong a part in sociodemographic differences in the diet of children in the early 1950s as did the strict, post-war food rationing that prevailed. In consequence, nutritional equality was not achieved, and the relatively low intake of antioxidant vitamins during early childhood in certain population groups may have compromised health in the long term.

Life course health development: an integrated framework for developing health, policy, and research

The life course health development (LCHD) framework organizes research from several fields into a conceptual approach explaining how individual and population health develops and how developmental trajectories are determined by interactions between biological and environmental factors during the lifetime. This approach thus provides a construct for interpreting how people's experiences in the early years of life influence later health conditions and functional status. By focusing on the relationship between experiences and the biology of development, the LCHD framework offers a better understanding of how diseases occur. By suggesting new strategies for health measurement, service delivery, and research, as well as for improving health outcomes, this framework also supports health care-purchasing strategies to develop health throughout life and to build human health capital.

Comparing social inequalities in health in Spain: 1987 and 1995/97

To evaluate the trend in social inequalities in health in Spain between 1987 and 1995/97, we carried out a secondary analysis of the Spanish National Interview Surveys from 1987, 1995 and 1997. We studied less-than-good perceived general health and four chronic conditions--heart disease, diabetes mellitus, chronic bronchitis/asthma and allergies--by social class and educational level in men and women aged 25-74 years. Among men, the age-adjusted prevalence rate ratio of less-than-good perceived general health by social class decreased from 1.32 to 1.23 between 1987 and 1995,97: however, the prevalence rate ratio by educational level increased from 1.47 to 1.57. Among women, the prevalence rate ratio of less-than-good perceived general health increased between the first and second period as much by social class from 1.18 to 1.26, as by educational level--from 1.59 to 1.66. For heart disease the age-adjusted prevalence rate ratio by social class among men was 1.12 in 1987 and 0.72 in 1995/97, while the prevalence rate ratio by educational level was around I in both periods, among women, the prevalence rate ratio for heart disease by social class was the same in 1987 and in 1995/97, but the prevalence rate ratio by educational level increased between the first and second period. For diabetes mellitus and chronic bronchitis/asthma, the prevalence rate ratio increased by social class and educational level between the first and second period in both men and women. Finally, the prevalence rate ratio for allergies was always < 1, although its magnitude increased between 1987 and 1995/97. In general, health inequalities were larger by educational level than by social class and were larger in women than in men. Inequalities in perceived general health, diabetes mellitus and chronic bronchitis/asthma increased in Spain between 1987 and 1995/97.

Epidemiology of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of world-wide mortality and disability. On average approximately 5-15% of adults in industrialized countries have COPD defined by spirometry. In 1990, COPD was considered to be at the twelfth position world-wide as a cause of combined mortality and disability but is expected to become the fifth cause by the year 2020. COPD has a chronic long-lasting course characterized by irreversible decline of forced expiratory volume in one second (FEV1), increasing presence of dyspnoea and other respiratory symptoms, and progressive deterioration of health status. After diagnosis the 10-yr survival rate is approximately 50% with more than one-third of patients dying due to respiratory insufficiency. Several environmental exposures such as air pollution increase the risk of death in COPD patients. The aetiology of COPD is overwhelmingly dominated by smoking although many other factors could play a role. Particular genetic variants are likely to increase the susceptibility to environmental factors although little is known about which are the relevant genes. There is clear evidence about the role of the alpha-1-antitrypsin but the fraction of COPD attributable to the relevant variants is only 1%. Phenotypic traits that are considered to play a role in the development of COPD include sex, with females being at a higher risk, bronchial responsiveness and atopy. There is strong causal evidence regarding the relationship between smoking and COPD with decline in FEVI levelling off after smoking cessation. Passive smoking has been found to be associated with a small though statistically significant decline in FEV1. Other risk factors that are likely to be relevant in the development of COPD are occupation, low socioeconomic status, diet and possibly some environmental exposures in early life. Although there is accumulating evidence that oxygen therapy, pharmacological treatment and rehabilitation may improve the course of chronic obstructive pulmonary disease, preventing smoking continues to be the most relevant measure, not only to prevent chronic obstructive pulmonary disease, but also to arrest its development.

Animal models of asthma: potential usefulness for studying health effects of inhaled particles

Asthma is now recognized to be a chronic inflammatory disease that affects the whole lung. Incidence appears to be increasing despite improved treatment regimens. There is substantial epidemiological evidence suggesting a relationship between the incidence and severity of asthma (e.g., hospitalizations) and exposure to increased levels of air pollution, especially fine and ultrafine particulate material, in susceptible individuals. There have been a few studies in animal models that support this concept, but additional animal studies to test this hypothesis are needed. However, such studies must be performed with awareness of the strengths and weaknesses of the currently available animal models. For studies in mice, the most commonly used animal, a broad spectrum of molecular and immunological tools is available, particularly to study the balance between Th1 and Th2 responses, and inbred strains may be useful for genetic dissection of susceptibility to the disease. However, the mouse is a poor model for bronchoconstriction or localized immune responses that characterize the human disease. In contrast, allergic lung diseases in dogs and cats may more accurately model the human condition, but fewer tools are available for characterization of the mechanisms. Finally, economic issues as well as reagent availability limit the utility of horses, sheep, and primates.

Height and risk of death among men and women: aetiological implications of associations with cardiorespiratory disease and cancer mortality

OBJECTIVES

Height is inversely associated with cardiovascular disease mortality risk and has shown variable associations with cancer incidence and mortality. The interpretation of findings from previous studies has been constrained by data limitations. Associations between height and specific causes of death were investigated in a large general population cohort of men and women from the West of Scotland.

DESIGN

Prospective observational study.

SETTING

Renfrew and Paisley, in the West of Scotland.

SUBJECTS

7052 men and 8354 women aged 45-64 were recruited into a study in Renfrew and Paisley, in the West of Scotland, between 1972 and 1976. Detailed assessments of cardiovascular disease risk factors, morbidity and socioeconomic circumstances were made at baseline.

MAIN OUTCOME MEASURES

Deaths during 20 years of follow up classified into specific causes.

RESULTS

Over the follow up period 3347 men and 2638 women died. Height is inversely associated with all cause, coronary heart disease, stroke, and respiratory disease mortality among men and women. Adjustment for socioeconomic position and cardiovascular risk factors had little influence on these associations. Height is strongly associated with forced expiratory volume in one second (FEV1) and adjustment for FEV1 considerably attenuated the association between height and cardiorespiratory mortality. Smoking related cancer mortality is not associated with height. The risk of deaths from cancer unrelated to smoking tended to increase with height, particularly for haematopoietic, colorectal and prostate cancers. Stomach cancer mortality was inversely associated with height. Adjustment for socioeconomic position had little influence on these associations.

CONCLUSION

Height serves partly as an indicator of socioeconomic circumstances and nutritional status in childhood and this may underlie the inverse associations between height and adulthood cardiorespiratory mortality. Much of the association between height and cardiorespiratory mortality was accounted for by lung function, which is also partly determined by exposures acting in childhood. The inverse association between height and stomach cancer mortality probably reflects Helicobacter pylori infection in childhood resulting in--or being associated with--shorter height. The positive associations between height and several cancers unrelated to smoking could reflect the influence of calorie intake during childhood on the risk of these cancers.

Income and health: what is the nature of the relationship?

The aim of this article is to examine the relationship between income and morbidity, both before and after controlling for other socio-economic variables. We use data from the Health and Lifestyle Survey (first wave), a national sample survey of adults, aged 18 upwards, in England, Wales and Scotland, conducted in 1984-1985. In total, 9003 interviews were achieved. We examine the shape of the relationship between household equivalised income and height, waist-hip ratio, respiratory function (FEV1), malaise, limiting longterm illness. These indices of morbidity, both self-reported and measured, are approximately linearly related to the logarithm of income, in all except very high and low incomes (this means that increasing income is associated with better health, but that there are diminishing returns at higher levels of income). A doubling of income is associated with a similar effect on health, regardless of the point at which this occurs, providing this is within the central portion (10-90%) of the income distribution. The effect of income on the health measures is comparable to that of the other socio-economic variables in combination. The shape of the relationship found between income and health is compatible with worse health in countries with greater income inequality, without the need to postulate any direct effect of income inequality itself.

Hospitalization for lung disease in early childhood and asthma symptoms in young adulthood

Longitudinal studies have reported an association between early childhood lung disease and adult respiratory disease. This issue has not been addressed in the Nordic countries. We studied the association between hospitalization for lung disease in early childhood and asthma in young adulthood in a Norwegian population sample, while estimating the attributable fraction of childhood hospitalization. A population-based survey in Bergen, Norway included a random sample of 4300 subjects aged 20-44 years, of whom 80% responded. The effect of hospitalization for lung disease before the age of 2 years on asthma in adulthood was analysed by logistic and polytomous logistic regressions, adjusting for related variables. Adjusted attributable fractions were estimated from these models. The risk for different measures of asthma was significantly increased in the 103 persons reporting childhood hospitalization (airways symptoms: OR from 1.9 to 2.9; asthma medication: OR = 2.8). The associations with airways symptoms were stronger in women (OR from 2.6 to 5.3) than in men (OR from 1.4 to 2.4). Given a causal association, adjusted attributable fractions showed that childhood lung disease causing hospitalization explained 4% of asthma symptoms. Early childhood hospitalization for lung disease was related to asthma symptoms in young Norwegian adults, more strongly in women than in men. Only a minor proportion of asthma symptoms in this age group could be related to hospitalization for lung disease in early childhood.