Giuseppe Nicola Giordano

The impact of changes in different aspects of social capital and material conditions on self-rated health over time: A longitudinal cohort study

Individual aspects of social capital have been shown to have significant associations with health outcomes. However, research has seldom tested different elements of social capital simultaneously, whilst also adjusting for other well-known health determinants over time. This longitudinal individual-level study investigates how temporal changes in social capital, together with changes in material conditions and other health determinants affect associations with self-rated health over a six year period. We use data from the British Household Panel Survey, a randomly selected cohort which is considered representative of the United Kingdoms population, with the same individuals (N=9303) providing responses to identical questions in 1999 and 2005. Four measures of social capital were used: interpersonal trust, social participation, civic participation and informal social networks. Material conditions were measured by total income (both individual and weighted household income), net of taxation. Other health determinants included age, gender, smoking, marital status and social class. After the baseline sample was stratified by health status, associations were examined between changes in health status and changes in all other considered variables. Simultaneous adjustment revealed that inability to trust demonstrated a significant association with deteriorating self-rated health, whereas increased levels of social participation were significantly associated with improved health status over time. Low levels of household and individual income also demonstrated significant associations with deteriorating self-rated health. In conclusion, it seems that interpersonal trust and social participation, considered valid indicators of social capital, appear to be independent predictors of self-rated health, even after adjusting for other well-known health determinants. Understandably, how trust and social participation influence health outcomes may help resolve the debate surrounding the role of social capital within the field of public health.

Social capital and health—Purely a question of context?

Debate still surrounds which level of analysis (individual vs. contextual) is most appropriate to investigate the effects of social capital on health. Applying multilevel ecometric analyses to British Household Panel Survey data, we estimated fixed and random effects between five individual-, household- and small area-level social capital indicators and general health. We further compared the variance in health attributable to each level using intraclass correlations. Our results demonstrate that association between social capital and health depends on indicator type and level investigated, with one quarter of total individual-level health variance found at the household level. However, individual-level social capital variables and other health determinants appear to influence contextual-level variance the most.

The association between cannabis abuse and subsequent schizophrenia: a Swedish national co-relative control study

Background Although cannabis abuse (CA) is known to be associated with schizophrenia, the causal nature of this association is unclear, with prodromal effects complicating its interpretation. Method From Swedish national registry databases, we used a co-relative case–control design with full-sibling, half-sibling and first-cousin comparisons, alongside a general Swedish population sample. Using ICD codes, 5456 individuals with an initial diagnosis of schizophrenia (2000–2010) were matched with five schizophrenia-free controls. We further identified first-cousin, half-sibling and full-sibling pairs discordant for CA and statistically extrapolated results for discordant monozygotic (MZ) twins. Results Within the general Swedish population, CA was strongly associated with later schizophrenia [odds ratio (OR) 10.44, 95% confidence interval (CI) 8.99–12.11]. This association was substantially attenuated both by increasing temporal delays between CA exposure and schizophrenia diagnosis and by controlling for increasing degrees of familial confounding. Extrapolated discordant MZ pairs suggested that fully controlling for confounding familial factors reduced the association between CA and later schizophrenia to more modest levels (ORs of approximately 3.3 and 1.6 with 3- and 7-year temporal delays respectively). Opiate, sedative, cocaine/stimulant and hallucinogen abuse were also strongly associated with subsequent schizophrenia in the general population. After controlling for familial confounding, only cocaine/stimulant exposure remained associated. Conclusions CA has an appreciable causal impact on future risk for schizophrenia. However, population-based estimates of cannabis–schizophrenia co-morbidity substantially overestimate their causal association. Predictions of the cases of schizophrenia that might be prevented by reduced cannabis consumption based on population associations are therefore likely to be considerably overestimated.

Trust and health: testing the reverse causality hypothesis

Background Social capital research has consistently shown positive associations between generalised trust and health outcomes over 2 decades. Longitudinal studies attempting to test causal relationships further support the theory that trust is an independent predictor of health. However, as the reverse causality hypothesis has yet to be empirically tested, a knowledge gap remains. The aim of this study, therefore, was to investigate if health status predicts trust. Methods Data employed in this study came from 4 waves of the British Household Panel Survey between years 2000 and 2007 (N=8114). The sample was stratified by baseline trust to investigate temporal relationships between prior self-rated health (SRH) and changes in trust. We used logistic regression models with random effects, as trust was expected to be more similar within the same individuals over time. Results From the ‘Can trust at baseline’ cohort, poor SRH at time (t−1) predicted low trust at time (t) (OR=1.38). Likewise, good health predicted high trust within the ‘Cannot’ trust cohort (OR=1.30). These patterns of positive association remained after robustness checks, which adjusted for misclassification of outcome (trust) status and the existence of other temporal pathways. Conclusions This study offers empirical evidence to support the circular nature of trust/health relationship. The stability of association between prior health status and changes in trust over time differed between cohorts, hinting at the existence of complex pathways rather than a simple positive feedback loop.

Testing the association between social capital and health over time: a family-based design

BackgroundThe past decade has seen a vast increase in empirical research investigating associations between social capital and health outcomes. Literature reviews reveal ‘generalized trust’ and ‘social participation’ to be the most robust of the commonly used social capital proxies, both showing positive association with health outcomes. However, this association could be confounded by unmeasured factors, such as the shared environment. Currently, there is a distinct lack of social capital research that takes into account such residual confounding.MethodsUsing data from the United Kingdom’s British Household Panel Survey (BHPS) (waves thirteen to eighteen, N = 6982), this longitudinal, multilevel study investigates the validity of the association between trust, social participation and self-rated health using a family-based design. As the BHPS samples on entire households, we employed ‘mean’ and ‘difference from the mean’ aggregate measures of social capital, the latter of which is considered a social capital measurement that is not biased by the shared environment of the household. We employed Generalized Estimating Equations for all analyses, our two-level model controlling for correlation at the household level.ResultsResults show that after adjusting for the shared environment of the household over a six year period, the association between social participation and self-rated health was fully attenuated (OR = 0.97 (95% confidence interval 0.89-1.06)), while the association with trust remained significant (OR = 1.11 (1.02-1.20)). Other health determinants, such as being a smoker, having no formal qualifications and being unemployed maintain their associations with poor self-rated health.ConclusionsThe association between social capital (specifically trust and social participation) and self-rated health appear to be confounded by shared environmental factors not previously considered by researchers. However, the association with trust remains, adding to existing empirical evidence that generalized trust may be an independent predictor of health.

Lifestyle precision medicine: the next generation in type 2 diabetes prevention?

The driving force behind the current global type 2 diabetes epidemic is insulin resistance in overweight and obese individuals. Dietary factors, physical inactivity, and sedentary behaviors are the major modifiable risk factors for obesity. Nevertheless, many overweight/obese people do not develop diabetes and lifestyle interventions focused on weight loss and diabetes prevention are often ineffective. Traditionally, chronically elevated blood glucose concentrations have been the hallmark of diabetes; however, many individuals will either remain ‘prediabetic’ or regress to normoglycemia. Thus, there is a growing need for innovative strategies to tackle diabetes at scale. The emergence of biomarker technologies has allowed more targeted therapeutic strategies for diabetes prevention (precision medicine), though largely confined to pharmacotherapy. Unlike most drugs, lifestyle interventions often have systemic health-enhancing effects. Thus, the pursuance of lifestyle precision medicine in diabetes seems rational. Herein, we review the literature on lifestyle interventions and diabetes prevention, describing the biological systems that can be characterized at scale in human populations, linking them to lifestyle in diabetes, and consider some of the challenges impeding the clinical translation of lifestyle precision medicine.

The 2008 financial crisis: Changes in social capital and its association with psychological wellbeing in the United Kingdom – A panel study

The global financial crisis of 2008 was described by the IMF as the worst recession since the Great Depression. This historic event provided the backdrop to this United Kingdom (UK) longitudinal study of changes in associations between social capital and psychological wellbeing. Past longitudinal studies have reported that the presence of social capital may buffer against adverse mental health outcomes. This study adds to existing literature by employing data from the British Household Panel Survey and tracking the same individuals (N = 11,743) pre- and immediately post-crisis (years 2007-09). With longitudinal, multilevel logistic regression modelling, we aimed to compare the buffering effects of individual-level social capital (generalised trust and social participation) against worse psychological wellbeing (GHQ-12) during and immediately after the 2008 financial crisis. After comparing the same individuals over time, results showed that stocks of social capital (generalised trust) were significantly depleted across the UK during the crisis, from 40% trusting others in 2007 to 32% in 2008. Despite this drop, the buffering effect of trust against worse psychological wellbeing was pronounced in 2008; those not trusting had an increased risk of worse psychological wellbeing in 2008 compared with the previous year in fully adjusted models (OR = 1.49, 95% CI (1.34-1.65). Levels of active participation increased across the timeframe of this study but were not associated with psychological health. From our empirical evidence, decision makers should be made aware of how events such as the crisis (and the measures taken to counter its effects) could negatively impact on a Nations trust levels. Furthermore, past research implies that the positive effects of trust on psychological wellbeing evident in this study may only be short-term; therefore, decision makers should also prioritise policies that restore trust levels to improve the psychological wellbeing of the population.

Age, period and cohort trends in drug abuse hospitalizations within the total Swedish population (1975-2010).

BACKGROUND The societal consequences of drug abuse (DA) are severe and well documented, the World Health Organization recommending tracking of population trends for effective policy responses in treatment of DA and delivery of health care services. However, to correctly identify possible sources of DA change, one must first disentangle three different time-related influences on the need for treatment due to DA: age effects, period effects and cohort effects. METHODS We constructed our main Swedish national DA database (spanning four decades) by linking healthcare data from the Swedish Hospital Discharge Register to individuals, which included hospitalisations in Sweden for 1975-2010. All hospitalized DA cases were identified by ICD codes. Our Swedish national sample consisted of 3078,129 men and 2921,816 women. We employed a cross-classified multilevel logistic regression model to disentangle any net age, period and cohort effects on DA hospitalization rates. RESULTS We found distinct net age, period and cohort effects, each influencing the predicted probability of hospitalisation for DA in men and women. Peak age for DA in both sexes was 33-35 years; net period effects showed an increase in hospitalisation for DA from 1996 to 2001; and in birth cohorts 1968-1974, we saw a considerable reduction (around 75%) in predicted probability of hospitalisation for DA. CONCLUSIONS The use of hospital admissions could be regarded as a proxy of the populations health service use for DA. Our results may thus constitute a basis for effective prevention planning, treatment and other appropriate policy responses.

The 2005 London terror attacks: An investigation of changes in psychological wellbeing and social capital pre- and post-attacks (2003-07)-A UK panel study

The London public transport suicide bombings, which occurred on 7th July 2005, were described as the worst single terrorist atrocity on British soil to date. Past acts of terrorism have been associated with deterioration in population mental health. They may also negatively impact levels of social capital, which is considered a buffer against poor mental health outcomes. By employing panel data from the British Household Panel Survey and following the same individuals (NT=9287) three times over a five-year period (2003, 2005 and 2007), the aim of this longitudinal multilevel study was to investigate: (i) the impact of terrorism on individual-level social capital (generalised trust and social participation) across the UK; and (ii) the buffering effects of social capital on psychological wellbeing (GHQ-12). By comparing 2005 and 2007 covariate values (including the two social capital proxies) against their pre-terror baseline (2003) measurements in two separate multilevel logistic regression models, we examined the immediate and longer-term effects of the 2005 attacks on our GHQ-12 outcome. Compared to baseline, generalised trust dropped from 44% to 36% immediately post-terror attacks in 2005, while local participation increased from 45.8% to 47.5%. Social capital levels started to return to baseline levels by 2007, yet both proxies maintained independent buffering effects against poor GHQ-12 scores in years 2005 and 2007. From this empirical evidence, it seems that though generalised trust levels are negatively affected by acts of terrorism, the accompanying increase in local active participation may aid in the re-establishment of societal norms and beliefs in later years. Decision makers should be aware that such atrocities may negatively impact on populations’ generalised trust in the shorter-term. To safeguard against losing this buffer against poor mental health outcomes, local active participation should be encouraged.

Discovery of biomarkers for glycaemic deterioration before and after the onset of type 2 diabetes: an overview of the data from the epidemiological studies within the IMI DIRECT Consortium

Background and aims: Understanding the aetiology, clinical presentation and prognosis of type 2 diabetes (T2D) and optimizing its treatment might be facilitated by biomarkers that help predict a person’s susceptibility to the risk factors that cause diabetes or its complications, or response to treatment. The IMI DIRECT (Diabetes Research on Patient Stratification) Study is a European Union (EU) Innovative Medicines Initiative (IMI) project that seeks to test these hypotheses in two recently established epidemiological cohorts. Here, we describe the characteristics of these cohorts at baseline and at the first main follow-up examination (18-months). Materials and methods: From a sampling-frame of 24,682 European-ancestry adults in whom detailed health information was available, participants at varying risk of glycaemic deterioration were identified using a risk prediction algorithm and enrolled into a prospective cohort study (n=2127) undertaken at four study centres across Europe (Cohort 1: prediabetes). We also recruited people from clinical registries with recently diagnosed T2D (n=789) into a second cohort study (Cohort 2: diabetes). The two cohorts were studied in parallel with matched protocols. Endogenous insulin secretion and insulin sensitivity were modelled from frequently sampled 75g oral glucose tolerance (OGTT) in Cohort 1 and with mixed-meal tolerance tests (MMTT) in Cohort 2. Additional metabolic biochemistry was determined using blood samples taken when fasted and during the tolerance tests. Body composition was assessed using MRI and lifestyle measures through self-report and objective methods. Results: Using ADA-2011 glycaemic categories, 33% (n=693) of Cohort 1 (prediabetes) had normal glucose regulation (NGR), and 67% (n=1419) had impaired glucose regulation (IGR). 76% of the cohort was male, age=62(6.2) years; BMI=27.9(4.0) kg/m2; fasting glucose=5.7(0.6) mmol/l; 2-hr glucose=5.9(1.6) mmol/l [mean(SD)]. At follow-up, 18.6(1.4) months after baseline, fasting glucose=5.8(0.6) mmol/l; 2-hr OGTT glucose=6.1(1.7) mmol/l [mean(SD)]. In Cohort 2 (diabetes): 65% (n=508) were lifestyle treated (LS) and 35% (n=271) were lifestyle + metformin treated (LS+MET). 58% of the cohort was male, age=62(8.1) years; BMI=30.5(5.0) kg/m2; fasting glucose=7.2(1.4)mmol/l; 2-hr glucose=8.6(2.8) mmol/l [mean(SD)]. At follow-up, 18.2(0.6) months after baseline, fasting glucose=7.8(1.8) mmol/l; 2-hr MMTT glucose=9.5(3.3) mmol/l [mean(SD)]. Conclusion: The epidemiological IMI DIRECT cohorts are the most intensely characterised prospective studies of glycaemic deterioration to date. Data from these cohorts help illustrate the heterogeneous characteristics of people at risk of or with T2D, highlighting the rationale for biomarker stratification of the disease - the primary objective of the IMI DIRECT consortium. Abbreviations: ASAT Abdominal subcutaneous adipose tissue DIRECT Diabetes Research on Patient Stratification EU European Union MMTT Mixed-meal tolerance test MRI Magnetic resonance imaging hpfVM High-pass filtered vector magnitude IAAT Intra-abdominal adipose tissue IGR Impaired glucose regulation IMI Innovative Medicines Initiative ME multiecho NGR Normal glucose regulation OGTT Oral glucose tolerance test PA Physical activity TAAT Total abdominal adipose tissue T2D Type 2 Diabetes