Socio-economic position at three points in life in association with type 2 diabetes and impaired glucose tolerance in middle-aged Swedish men and women

Identification and epidemiological characterization of Type-2 diabetes sub-population using an unsupervised machine learning approach

Background

Studies on Type-2 Diabetes Mellitus (T2DM) have revealed heterogeneous sub-populations in terms of underlying pathologies. However, the identification of sub-populations in epidemiological datasets remains unexplored. We here focus on the detection of T2DM clusters in epidemiological data, specifically analysing the National Family Health Survey-4 (NFHS-4) dataset from India containing a wide spectrum of features, including medical history, dietary and addiction habits, socio-economic and lifestyle patterns of 10,125 T2DM patients.

Methods

Epidemiological data provide challenges for analysis due to the diverse types of features in it. In this case, applying the state-of-the-art dimension reduction tool UMAP conventionally was found to be ineffective for the NFHS-4 dataset, which contains diverse feature types. We implemented a distributed clustering workflow combining different similarity measure settings of UMAP, for clustering continuous, ordinal and nominal features separately. We integrated the reduced dimensions from each feature-type-distributed clustering to obtain interpretable and unbiased clustering of the data.

Results

Our analysis reveals four significant clusters, with two of them comprising mainly of non-obese T2DM patients. These non-obese clusters have lower mean age and majorly comprises of rural residents. Surprisingly, one of the obese clusters had 90% of the T2DM patients practising a non-vegetarian diet though they did not show an increased intake of plant-based protein-rich foods.

Conclusions

From a methodological perspective, we show that for diverse data types, frequent in epidemiological datasets, feature-type-distributed clustering using UMAP is effective as opposed to the conventional use of the UMAP algorithm. The application of UMAP-based clustering workflow for this type of dataset is novel in itself. Our findings demonstrate the presence of heterogeneity among Indian T2DM patients with regard to socio-demography and dietary patterns. From our analysis, we conclude that the existence of significant non-obese T2DM sub-populations characterized by younger age groups and economic disadvantage raises the need for different screening criteria for T2DM among rural Indian residents.

Sociodemographic and lifestyle-related risk factors for identifying vulnerable groups for type 2 diabetes: a narrative review with emphasis on data from Europe

BACKGROUND

Type 2 diabetes mellitus (T2DM) comprises the vast majority of all diabetes cases in adults, with alarmingly increasing prevalence over the past few decades worldwide. A particularly heavy healthcare burden of diabetes is noted in Europe, where 8.8% of the population aged 20-79 years is estimated to have diabetes according to the International Diabetes Federation. Multiple risk factors are implicated in the pathogenesis of T2DM with complex underlying interplay and intricate gene-environment interactions. Thus, intense research has been focused on studying the role of T2DM risk factors and on identifying vulnerable groups for T2DM in the general population which can then be targeted for prevention interventions.

METHODS

For this narrative review, we conducted a comprehensive search of the existing literature on T2DM risk factors, focusing on studies in adult cohorts from European countries which were published in English after January 2000.

RESULTS

Multiple lifestyle-related and sociodemographic factors were identified as related to high T2DM risk, including age, ethnicity, family history, low socioeconomic status, obesity, metabolic syndrome and each of its components, as well as certain unhealthy lifestyle behaviors. As Europe has an increasingly aging population, multiple migrant and ethnic minority groups and significant socioeconomic diversity both within and across different countries, this review focuses not only on modifiable T2DM risk factors, but also on the impact of pertinent demographic and socioeconomic factors.

CONCLUSION

In addition to other T2DM risk factors, low socioeconomic status can significantly increase the risk for prediabetes and T2DM, but is often overlooked. In multinational and multicultural regions such as Europe, a holistic approach, which will take into account both traditional and socioeconomic/socioecological factors, is becoming increasingly crucial in order to implement multidimensional public health programs and integrated community-based interventions for effective T2DM prevention.

Early-life factors are associated with waist circumference and type 2 diabetes among Ghanaian adults: The RODAM Study

Early-life experiences may fuel the emergence of obesity and type 2 diabetes among African populations. We evaluated childhood socio-economic status (SES) and childhood nutritional status as risk factors for increased waist circumference and type 2 diabetes among Ghanaian adults. In the multi-center, cross-sectional Research on Obesity and Diabetes among African Migrants (RODAM) Study, we calculated associations (adjusted for demographics and lifestyle) of parental education and anthropometric markers of childhood nutrition [leg length, leg length-to-height ratio (LHR)] with waist circumference and type 2 diabetes, respectively. Among 5,575 participants (mean age: 46.2 years; 62% female), lower education of either parent (vs. higher) was consistently associated with higher waist circumference (∆: 1.6-3.4 cm). Lower father's education tended to increase the odds of type 2 diabetes by 50% in women (95% confidence interval (CI): 1.0, 2.4). Reduced leg length and LHR were associated with higher waist circumference. But only in men, leg length was inversely related to type 2 diabetes (OR per 1 standard deviation decrease: 1.1; 95% CI: 1.0, 1.3). In this study, markers of poor childhood SES and early-life nutritional status relate to abdominal obesity in men and women and to type 2 diabetes in men. Thus, prevention efforts should start in early childhood.

Issues in Defining the Burden of Prediabetes Globally

PURPOSE OF REVIEW

Using a global perspective, this review collates evidence on the heterogeneity of prediabetes definitions and diagnostic methods, their clinical and public health implications, and discusses possible options for improvement.

RECENT FINDINGS

Our review notes that the concept of prediabetes is increasingly recognized worldwide, but against a background of non-uniform definition and diagnostic criteria. This results in widely varying burden estimation. Current evidence shows a variety of prediabetes phenotypes. This reflects biological and diagnostic heterogeneity, resulting from the use of different tests (glucose or HbA_1C) and thresholds to define prediabetes. The biological and diagnostic variabilities have implications for the characterization of the burden of prediabetes, natural history, prognosis, screening, implementation of lifestyle or drug interventions to mitigate related health risks, and monitoring of the effects of such interventions.

The contribution of health behaviors to socioeconomic inequalities in health: A systematic review

Unhealthy behaviors and their social patterning have been frequently proposed as factors mediating socioeconomic differences in health. However, a clear quantification of the contribution of health behaviors to the socioeconomic gradient in health is lacking. This study systematically reviews the role of health behaviors in explaining socioeconomic inequalities in health. Published studies were identified by a systematic review of PubMed, Embase and Web-of-Science. Four health behaviors were considered: smoking, alcohol consumption, physical activity and diet. We restricted health outcomes to cardiometabolic disorders and mortality. To allow comparison between studies, the contribution of health behaviors, or the part of the socioeconomic gradient in health that is explained by health behaviors, was recalculated in all studies according to the absolute scale difference method. We identified 114 articles on socioeconomic position, health behaviors and cardiometabolic disorders or mortality from electronic databases and articles reference lists. Lower socioeconomic position was associated with an increased risk of all-cause mortality and cardiometabolic disorders, this gradient was explained by health behaviors to varying degrees (minimum contribution -43%; maximum contribution 261%). Health behaviors explained a larger proportion of the SEP-health gradient in studies conducted in North America and Northern Europe, in studies examining all-cause mortality and cardiovascular disease, among men, in younger individuals, and in longitudinal studies, when compared to other settings. Of the four behaviors examined, smoking contributed the most to social inequalities in health, with a median contribution of 19%. Health behaviors contribute to the socioeconomic gradient in cardiometabolic disease and mortality, but this contribution varies according to population and study characteristics. Nevertheless, our results should encourage the implementation of interventions targeting health behaviors, as they may reduce socioeconomic inequalities in health and increase population health.

Socio-economic status influences access to second-line disease modifying treatment in Relapsing Remitting Multiple Sclerosis patients

Objective

In MS, Socio-Economic status (SES) may influence healthcare and access to disease-modifying treatments (DMTs). Optimising delays to switch patients to a second-line DMT may hamper disease progression most effectively and achieve long term disease control. The objective of this study is to identify the influence of SES on the delay between first and second line DMT in RRMS patients, in Western-Normandy, France.

Methods

The association between SES and the delay to access a second-line DMT were studied using data from the MS registry of Western-Normandy including 733 patients with a diagnosis of RRMS during the period in question [1982–2011]. We used the European Deprivation Index (EDI), a score with a rank level inversely related to SES. We performed multivariate adjusted Cox models for studying EDI effect on the delay between first and second line DMT.

Results

No significant influence of SES was observed on delay to access a second-line DMT if first-line DMT exposure time was less than 5 years. After 5 years from initiation of first-line treatment the risk of accessing a second-line DMT is 3 times higher for patients with lower deprivation indices (1^st quintile of EDI) ([HR] 3.14 95%CI [1.72–5.72], p-value<0.001) compared to patients with higher values (EDI quintiles 2 to 5).

Interpretation

In RRMS, a high SES may facilitate access to a second-line DMT a few years after first-line DMT exposure. Greater consideration should also be given to the SES of MS patients as a risk factor in therapeutic healthcare issues throughout medical follow-up.

Fractures in indigenous compared to non-indigenous populations: A systematic review of rates and aetiology

BACKGROUND

Compared to non-indigenous populations, indigenous populations experience disproportionately greater morbidity, and a reduced life expectancy; however, conflicting data exist regarding whether a higher risk of fracture is experienced by either population. We systematically evaluate evidence for whether differences in fracture rates at any skeletal site exist between indigenous and non-indigenous populations of any age, and to identify potential risk factors that might explain these differences.

METHODS

On 31 August 2016 we conducted a comprehensive computer-aided search of peer-reviewed literature without date limits. We searched PubMed, OVID, MEDLINE, CINAHL, EMBASE, and reference lists of relevant publications. The protocol for this systematic review is registered in PROSPERO, the International Prospective Register of systematic reviews (CRD42016043215). Using the World Health Organization reference population as standard, hip fracture incidence rates were re-standardized for comparability between countries.

RESULTS

Our search yielded 3227 articles; 283 potentially eligible articles were cross-referenced against predetermined criteria, leaving 27 articles for final inclusion. Differences in hip fracture rates appeared as continent-specific, with lower rates observed for indigenous persons in all countries except for Canada and Australia where the opposite was observed. Indigenous persons consistently had higher rates of trauma-related fractures; the highest were observed in Australia where craniofacial fracture rates were 22-times greater for indigenous compared to non-indigenous women. After adjustment for socio-demographic and clinical risk factors, approximately a three-fold greater risk of osteoporotic fracture and five-fold greater risk of craniofacial fractures was observed for indigenous compared to non-indigenous persons; diabetes, substance abuse, comorbidity, lower income, locality, and fracture history were independently associated with an increased risk of fracture.

CONCLUSIONS

The observed paucity of data and suggestion of continent-specific differences indicate an urgent need for further research regarding indigenous status and fracture epidemiology and aetiology. Our findings also have implications for communities, governments and healthcare professionals to enhance the prevention of trauma-related fractures in indigenous persons, and an increased focus on modifiable lifestyle behaviours to prevent osteoporotic fractures in all populations.

The association of early life socioeconomic conditions with prediabetes and type 2 diabetes: results from the Maastricht study

Background

Using cross-sectional data from The Maastricht Study, we examined the association of socioeconomic conditions in early life with prediabetes and T2DM in adulthood. We also examined potential mediating pathways via both adulthood socioeconomic conditions and adult BMI and health behaviours.

Methods

Of the 3263 participants (aged 40–75 years), 493 had prediabetes and 906 were diagnosed with T2DM. By using logistic regression analyses, the associations and possible mediating pathways were examined.

Results

Participants with low early life socioeconomic conditions had a 1.56 times higher odds of prediabetes (95% confidence interval (CI) = 1.21-2.02) and a 1.61 times higher odds of T2DM (95% CI = 1.31-1.99). The relation between low early life socioeconomic conditions and prediabetes was independent of current socioeconomic conditions (OR = 1.38, 95% CI = 1.05-1.80), whereas the relation with T2DM was not independent of current socioeconomic conditions (OR = 1.10, 95% CI = 0.87-1.37). BMI party mediated the association between early life socioeconomic conditions and prediabetes.

Conclusions

Socioeconomic inequalities starting in early life were associated with diabetes-related outcomes in adulthood and suggest the usefulness of early life interventions aimed at tackling these inequalities.

Electronic supplementary material

The online version of this article (doi:10.1186/s12939-017-0553-7) contains supplementary material, which is available to authorized users.

Subclinical hypothyroidism and diabetic nephropathy in Iranian patients with type 2 diabetes

PURPOSE

Association of subclinical hypothyroidism with type 2 diabetes and its complications has been previously documented. These reports were, however, inconclusive and mainly gathered from Chinese and East Asian populations. In this study, we aimed to determine the prevalence of subclinical hypothyroidism and its relationship with diabetic nephropathy in Iranian individuals with type 2 diabetes, drawn from a white Middle Eastern population with an increasing prevalence of diabetes.

METHODS

In this cross-sectional study, 255 Iranian participants with type 2 diabetes and without history of thyroid disorders were included. Patients with TSH > 4.2 mIU/L and normal T4 were classified as having subclinical hypothyroidism. Diabetic nephropathy was diagnosed based on abnormal 24-h urinary albumin or protein measurements (24-h urinary albumin ≥30 mg/day or 24-h urinary protein ≥150 mg/day). Multivariate logistic regression was employed to obtain the OR for the relationship between subclinical hypothyroidism and diabetic nephropathy.

RESULTS

We found that subclinical hypothyroidism and diabetic nephropathy were as prevalent as 18.1 and 41.2 %, respectively, among the participants. We also found that subclinical hypothyroidism was independently associated with higher rates of diabetic nephropathy, after multivariable adjustment (OR [95 % CI] 3.23 [1.42-7.37], p = 0.005).

CONCLUSIONS

We found that the prevalence of subclinical hypothyroidism in Iranian diabetic population was among the highest rates reported to date. Our data supported the independent association of subclinical hypothyroidism with diabetic nephropathy, calling for further investigations to evaluate their longitudinal associations.

Linking data on work, health and lifestyle to explain socio-occupational inequality in Danish register-based incidence of diabetes

AIMS

This study aimed to combine three consecutive cohorts representative of the general working population to estimate the lifestyle, work and health of the entire Danish working population and to explore the influence of these factors on socio-occupational inequality in relation to incident diabetes over ten years.

METHODS

This study linked the National Danish Diabetes Register with (a) three questionnaire rounds (1995, 2000, 2005) on work, health and lifestyle from the Danish Work Environment Cohort Study (DWECS) among 6823 representative Danish workers aged 30-59 years and (b) the different socio-occupational groups of the entire Danish population aged 30-59 years (n=1,833,756). The relative risk (RR) was calculated using a Poisson regression.

RESULTS

In DWECS, none of the investigated job factors was associated with incident diabetes. Lifestyle factors in terms of smoking (RR = 1.35; 95% confidence interval (CI) 1.07-1.70), high body mass index (overweight RR = 2.81; 95% CI 2.11-3.74 and obesity RR = 7.49; 95% CI 5.46-10.28) were risk factors for incident diabetes. When adjusted for health and lifestyle, there was no difference in diabetes risk among socio-occupational groups in DWECS. In the entire working population, there was a negative socio-occupational gradient for the risk of diabetes. Compared with professionals, workers in elementary occupations had the highest ten-year risk (RR = 2.06; 95% CI 2.01-2.12). CONCLUSIONS WE FOUND A SIGNIFICANT NEGATIVE SOCIO-OCCUPATIONAL GRADIENT IN THE RISK OF INCIDENT DIABETES HOWEVER, LIFESTYLE RATHER THAN WORK ENVIRONMENT APPEARS TO BE THE MOST IMPORTANT FACTOR AND ADJUSTING FOR THIS ALMOST ELIMINATED THE SOCIO-OCCUPATIONAL INEQUALITY FOR THE DEVELOPMENT OF DIABETES.

Socioeconomic Disparities in Weight and Behavioral Outcomes Among American Indian and Alaska Native Participants of a Translational Lifestyle Intervention Project

OBJECTIVE

To investigate possible socioeconomic disparities in weight and behavioral outcomes among American Indian and Alaska Native (AI/AN) participants in a translational diabetes prevention project.

RESEARCH DESIGN AND METHODS

We analyzed data from the Special Diabetes Program for Indians Diabetes Prevention (SDPI-DP) Program, an evidence-based lifestyle intervention to prevent diabetes in 36 AI/AN grantee sites. A total of 2,553 participants started the 16-session Lifestyle Balance Curriculum between 1 January 2006 and 31 July 2008. Linear mixed models were used to evaluate the relationships of participant and staff socioeconomic characteristics with weight and behavioral outcomes at the end of the curriculum.

RESULTS

A strong, graded association existed between lower household income and less BMI reduction, which remained significant after adjusting for other socioeconomic characteristics. Compared with others, participants with annual income <$15,000 also had less improvement in physical activity and unhealthy food consumption in bivariate models, but the relationships were only marginally significant in multivariate regressions. Furthermore, grantee sites with fewer professionally prepared staff were less successful at improving participant BMI and healthy food consumption than the other sites. The strong association between income and BMI reduction was reduced by 20-30% in the models with changes in diet variables but was unrelated to changes in physical activity.

CONCLUSIONS

Significant socioeconomic disparities exist in weight outcomes of lifestyle intervention at both participant and site staff levels. Helping low-income participants choose more affordable healthy foods and increasing the proportion of professionally trained staff might be practical ways to maximize the effectiveness of lifestyle interventions implemented in "real-world" settings.

Socioeconomic Status and the Prevalence of Type 2 Diabetes Among Adults in Northwest China

PURPOSE

The purpose of the study was to investigate (1) the associations of socioeconomic status, lifestyle risk factors, and the prevalence of newly diagnosed type 2 diabetes and (2) the mediating effects of lifestyle risk factors on the association of socioeconomic status and the prevalence of newly diagnosed type 2 diabetes among Chinese adults in northwest China.

METHODS

Based on a correlational design and random multistage sampling in communities (N = 3243), data were collected through face-to-face interviews and anthropometric measurements. Education, occupation, and income were considered indicators of socioeconomic status.

RESULTS

Approximately 7.5% persons interviewed had newly diagnosed type 2 diabetes. Chi-square analyses showed that higher socioeconomic indicators (higher income, nonmanual occupation) were associated with increased risk. Lifestyle risk factors, including alcohol use, unhealthy diet, and higher body mass index, were significantly positively associated with type 2 diabetes. Adjusting for demographic characteristics, hierarchical logistic regression analyses showed that unhealthy diet and high body mass index were significantly associated with type 2 diabetes.

CONCLUSIONS

Higher incomes and nonmanual occupations were related to a greater prevalence of type 2 diabetes, and high body mass index mediated these associations. These findings suggest that interventions for type 2 diabetes in China should be targeted at populations with high socioeconomic status and nonmanual occupations to reduce lifestyle risk factors and prevent diabetes.

Age- and sex-specific relationships between household income, education, and diabetes mellitus in Korean adults: the Korea National Health and Nutrition Examination Survey, 2008-2010

Background

To investigate the effects of age and sex on the relationship between socioeconomic status (SES) and the prevalence and control status of diabetes mellitus (DM) in Korean adults.

Methods

Data came from 16,175 adults (6,951 men and 9,227 women) over the age of 30 who participated in the 2008-2010 Korea National Health and Nutrition Examination Survey. SES was measured by household income or education level. The adjusted odds ratios (ORs) and corresponding 95% confidence intervals (95% CI) for the prevalence or control status of diabetes were calculated using multiple logistic regression analyses across household income quartiles and education levels.

Results

The household income-DM and education level-DM relationships were significant in younger age groups for both men and women. The adjusted ORs and 95% CI for diabetes were 1.51 (0.97, 2.34) and 2.28 (1.29, 4.02) for the lowest vs. highest quartiles of household income and education level, respectively, in women younger than 65 years of age (both P for linear trend < 0.05 with Bonferroni adjustment). The adjusted OR and 95% CI for diabetes was 2.28 (1.53, 3.39) for the lowest vs. highest quartile of household income in men younger than 65 (P for linear trend < 0.05 with Bonferroni adjustment). However, in men and women older than 65, no associations were found between SES and the prevalence of DM. No significant association between SES and the status of glycemic control was detected.

Conclusions

We found age- and sex-specific differences in the relationship of household income and education with the prevalence of DM in Korea. DM preventive care is needed for groups with a low SES, particularly in young or middle-aged populations.

Childhood socioeconomic disadvantage and prediabetes and diabetes in later life: a study of biopsychosocial pathways

OBJECTIVE

We examined the relationship between childhood socioeconomic status (SES) and glucoregulation in later life and used a life-course framework to examine critical periods and underlying pathways.

METHODS

Data came from the Midlife in the US (MIDUS) national study (n = 895). Childhood SES indicators retrospectively reported at MIDUS I were used to create a childhood SES disadvantage index. Adult SES disadvantage and potential pathways were measured at MIDUS I and included waist circumference, depressive symptoms, and physical activity. Glucose and hemoglobin A1c, measured approximately 9 to 10 years later at MIDUS II, were used to create the ordinal outcome measure (no diabetes/prediabetes/diabetes).

RESULTS

Childhood SES disadvantage predicted increased odds of prediabetes and diabetes net of age, sex, race, and smoking (odds ratio = 1.11, 95% confidence interval = 1.01-1.22). Childhood SES disadvantage predicted adult SES disadvantage (β = .26, p = .001) and the three key mediators: waist circumference (β = 0.10, p = .002), physical activity (β = -0.11, p = .001), and depressive symptoms (β = 0.07, p = .072). When childhood and adult SES disadvantage were in the same model, only adult SES predicted glucoregulation (odds ratio = 1.07, 95% confidence interval = 1.01-1.13). The SES disadvantage measures were no longer significantly associated with glucoregulation after including waist circumference, physical activity, and depressive symptoms, all of which were significant predictors of glucoregulation.

CONCLUSIONS

The consequences of childhood SES disadvantage are complex and include both critical period and pathway effects. The lack of a direct effect of childhood SES on glucoregulation does not negate the importance of early environment but suggests that early-life socioeconomic factors propel unequal life-course trajectories that ultimately influence health.

Sex specific incidence rates of type 2 diabetes and its risk factors over 9 years of follow-up: Tehran Lipid and Glucose Study

Objective

To investigate the population-based incidence of type 2 diabetes and its potential risk factors in a sex-split cohort of Iranian population.

Materials and Methods

A total of 8400 non-diabetic participants, aged ≥20 years (3620 men and 4780 women) entered the study. Crude and age standardized incidence rates per 1000 person-years were calculated for whole population and each sex separately. Cox proportional hazard models were used to evaluate hazard ratios (HR) and 95% confidence intervals for all potential risk factors in both uni-variable and multivariable models.

Results

During a median follow-up of 9.5 years, 736 new cases of diabetes were identified, including 433 women and 303 men. The annual crude and age-standardized incidence rates (95% CI) of diabetes in the total population were 10.6 (9.92–11.4) and 9.94 (7.39–13.6) per 1000 person-years of follow-up and the corresponding sex specific rates were 10.2 (9.13–11.4) and 9.36 (5.84–14.92) in men and 11.0 (9.99–12.0) and 10.1 (7.24–13.9) in women, respectively. In the multivariable model, the risk for incident diabetes was significantly associated with fasting and 2 hour post challenge plasma glucose as well as family history of diabetes in both men and women. However, among women, only the contribution of wrist circumference to incident diabetes achieved statistical significance [HR: 1.16 (1.03–1.31)] with waist/height ratio being marginally significant [HR: 1.02 (0.99–1.04)]; while among men, only body mass index was a significant predictor [HR: 1.12 (1.02–1.22)]. Additionally, low education level conferred a higher risk for incident diabetes only among men [HR: 1.80 (1.23–2.36); P for interaction with sex = 0.003].

Conclusion

Overall, sex did not significantly modify the impact of risk factors associated with diabetes among Iranian adults; however, among modifiable risk factors, the independent role of lower education and general adiposity in men and central adiposity in women might require different preventive strategies.

Incidence of Type 2 diabetes among occupational classes in Sweden: a 35-year follow-up cohort study in middle-aged men

AIMS

To assess if low occupational class was an independent predictor of Type 2 diabetes in men in Sweden over a 35-year follow-up, after adjustment for both conventional risk factors and psychological stress.

METHODS

A random population-based sample of 6874 men aged 47-56 years without a history of diabetes was divided into five occupational classes and the men were followed from 1970 to 2008. Diabetes cases were identified through the Swedish inpatient and death registers. Subdistribution hazard ratios (SHRs) and 95% CIs from competing risk regressions, cumulative incidence and conditional probabilities were calculated, after accounting for the risk of death attributed to other causes.

RESULTS

A total of 907 (13%) men with diabetes were identified over 35 years with a median follow-up of 27.9 years. The cumulative incidence of diabetes, when taking into account death as a competing event, was 11% in high officials, 12% in intermediate non-manual employees, 14% in assistant non-manual employees, 14% in skilled workers, and 16% in unskilled and semi-skilled workers. Men with unskilled and semi-skilled manual occupations had a significantly higher risk of diabetes than high officials (reference) after adjustment for age, BMI, hypertension, smoking and physical activity (SHR 1.39, 95% CI 1.08-1.78). Additional adjustment for self-reported psychological stress did not attenuate the results.

CONCLUSIONS

A low occupational class suggests a greater risk of Type 2 diabetes, independently of conventional risk factors and psychological stress.

The role of childhood social position in adult type 2 diabetes: evidence from the English Longitudinal Study of Ageing

BACKGROUND

Socioeconomic circumstances in childhood and early adulthood may influence the later onset of chronic disease, although such research is limited for type 2 diabetes and its risk factors at the different stages of life. The main aim of the present study is to examine the role of childhood social position and later inflammatory markers and health behaviours in developing type 2 diabetes at older ages using a pathway analytic approach.

METHODS

Data on childhood and adult life circumstances of 2,994 men and 4,021 women from English Longitudinal Study of Ageing (ELSA) were used to evaluate their association with diabetes at age 50 years and more. The cases of diabetes were based on having increased blood levels of glycated haemoglobin and/or self-reported medication for diabetes and/or being diagnosed with type 2 diabetes. Father's job when ELSA participants were aged 14 years was used as the measure of childhood social position. Current social characteristics, health behaviours and inflammatory biomarkers were used as potential mediators in the statistical analysis to assess direct and indirect effects of childhood circumstances on diabetes in later life.

RESULTS

12.6 per cent of participants were classified as having diabetes. A disadvantaged social position in childhood, as measured by father's manual occupation, was associated at conventional levels of statistical significance with an increased risk of type 2 diabetes in adulthood, both directly and indirectly through inflammation, adulthood social position and a risk score constructed from adult health behaviours including tobacco smoking and limited physical activity. The direct effect of childhood social position was reduced by mediation analysis (standardised coefficient decreased from 0.089 to 0.043) but remained statistically significant (p= 0.035). All three indirect pathways made a statistically significantly contribution to the overall effect of childhood social position on adulthood type 2 diabetes.

CONCLUSIONS

Childhood social position influences adult diabetes directly and indirectly through inflammatory markers, adulthood social position and adult health behaviours.

Association between socio-economic status and hemoglobin A1c levels in a Canadian primary care adult population without diabetes

BACKGROUND

Hgb A1c levels may be higher in persons without diabetes of lower socio-economic status (SES) but evidence about this association is limited; there is therefore uncertainty about the inclusion of SES in clinical decision support tools informing the provision and frequency of Hgb A1c tests to screen for diabetes. We studied the association between neighborhood-level SES and Hgb A1c in a primary care population without diabetes.

METHODS

This is a retrospective study using data routinely collected in the electronic medical records (EMRs) of forty six community-based family physicians in Toronto, Ontario. We analysed records from 4,870 patients without diabetes, age 45 and over, with at least one clinical encounter between January 1st 2009 and December 31st 2011 and one or more Hgb A1c report present in their chart during that time interval. Residential postal codes were used to assign neighborhood deprivation indices and income levels by quintiles. Covariates included elements known to be associated with an increase in the risk of incident diabetes: age, gender, family history of diabetes, body mass index, blood pressure, LDL cholesterol, HDL cholesterol, triglycerides, and fasting blood glucose.

RESULTS

The difference in mean Hgb A1c between highest and lowest income quintiles was -0.04% (p = 0.005, 95% CI -0.07% to -0.01%), and between least deprived and most deprived was -0.05% (p = 0.003, 95% CI -0.09% to -0.02%) for material deprivation and 0.02% (p = 0.2, 95% CI -0.06% to 0.01%) for social deprivation. After adjustment for covariates, a marginally statistically significant difference in Hgb A1c between highest and lowest SES quintile (p = 0.04) remained in the material deprivation model, but not in the other models.

CONCLUSIONS

We found a small inverse relationship between Hgb A1c and the material aspects of SES; this was largely attenuated once we adjusted for diabetes risk factors, indicating that an independent contribution of SES to increasing Hgb A1c may be limited. This study does not support the inclusion of SES in clinical decision support tools that inform the use of Hgb A1c for diabetes screening.

Independent roles of country of birth and socioeconomic status in the occurrence of type 2 diabetes

BACKGROUND

There is strong evidence based on previous studies that ethnicity and socioeconomic status are important determinants of diversity in the occurrence of diabetes. However, the independent roles of socioeconomic status, country of birth and lifestyle factors in the occurrence of type 2 diabetes have not been clearly identified. This study investigated the relationships between socioeconomic status, country of birth and type 2 diabetes in a large diverse sample of residents of New South Wales, Australia, and aged 45 years and over.

METHODS

The analysis used self-reported baseline questionnaire data from 266,848 participants in the 45 and Up Study. Educational attainment, work status and income were used as indicators of socioeconomic status. Logistic regression models were built to investigate associations between socioeconomic status, country of birth and type 2 diabetes.

RESULTS

The adjusted odds of type 2 diabetes were significantly higher for people born in many overseas countries, compared to Australian-born participants. Compared with participants who had a university degree or higher qualification, the adjusted odds ratio (OR) for diabetes was higher in all other educational categories. Diabetes was more prevalent in people who were retired, unemployed or engaged in other types of work, compared with people who were in paid work. The prevalence of diabetes was higher in people with lower incomes. Compared with people who earned more than $50,000, the adjusted OR for diabetes was 2.05 (95% CI 1.95-2.14) for people who had an income less than $20,000 per annum. The relationships between socioeconomic factors and country of birth and diabetes were attenuated slightly when all were included in the model. Addition of smoking, obesity and physical activity to the model had marked impacts on adjusted ORs for some countries of birth, but relationships between diabetes and all measures of socioeconomic status and country of birth remained strong and significant.

CONCLUSIONS

Country of birth and socioeconomic status are independent predictors of type 2 diabetes. However, in this population, country of birth had a stronger association with type 2 diabetes.

Associations between race, lifecourse socioeconomic position and prevalence of diabetes among US women and men: results from a population-based panel study

BACKGROUND

Few studies have examined the degree to which racial disparities in the development of diabetes are accounted by differences in lifecourse socioeconomic position (SEP). We assessed the association between race, lifecourse SEP measures and prevalence of diabetes in a representative US sample of black and white adults.

METHODS

A generalised estimating equations approach was used with a sample of 3497 adults from the Americans' Changing Lives study. Sex-specific models were calculated to compute prevalence ratios (PR) for associations of race and SEP with self-reported diagnoses of diabetes.

RESULTS

For men, childhood and adult SEP were unrelated to diabetes, and adjustment for lifecourse SEP had little effect on the excess diabetes in blacks (PR=1.56, 95% CI 1.11 to 2.21). Adjustment for measures of lifecourse SEP reduced the PR for the association between race and diabetes in women from 1.96 (95% CI 1.52 to 2.54) to 1.40 (95% CI 1.04 to 1.87) with the respondent's education responsible for most of the reduction in the association. However, diabetes was also inversely associated with father's education, and low SEP throughout the lifecourse was associated with a nearly threefold increase in diabetes (PR=2.89, 95% CI 2.10 to 3.99).

CONCLUSIONS

Racial disparities in diabetes existed among both men and women, but lifecourse SEP was related to diabetes only among women. The pathway and cumulative hypotheses for lifecourse SEP effects on diabetes may be especially salient for women.

Association of lifecourse socioeconomic status with chronic inflammation and type 2 diabetes risk: the Whitehall II prospective cohort study

BACKGROUND

Socioeconomic adversity in early life has been hypothesized to "program" a vulnerable phenotype with exaggerated inflammatory responses, so increasing the risk of developing type 2 diabetes in adulthood. The aim of this study is to test this hypothesis by assessing the extent to which the association between lifecourse socioeconomic status and type 2 diabetes incidence is explained by chronic inflammation.

METHODS AND FINDINGS

We use data from the British Whitehall II study, a prospective occupational cohort of adults established in 1985. The inflammatory markers C-reactive protein and interleukin-6 were measured repeatedly and type 2 diabetes incidence (new cases) was monitored over an 18-year follow-up (from 1991-1993 until 2007-2009). Our analytical sample consisted of 6,387 non-diabetic participants (1,818 women), of whom 731 (207 women) developed type 2 diabetes over the follow-up. Cumulative exposure to low socioeconomic status from childhood to middle age was associated with an increased risk of developing type 2 diabetes in adulthood (hazard ratio [HR] = 1.96, 95% confidence interval: 1.48-2.58 for low cumulative lifecourse socioeconomic score and HR = 1.55, 95% confidence interval: 1.26-1.91 for low-low socioeconomic trajectory). 25% of the excess risk associated with cumulative socioeconomic adversity across the lifecourse and 32% of the excess risk associated with low-low socioeconomic trajectory was attributable to chronically elevated inflammation (95% confidence intervals 16%-58%).

CONCLUSIONS

In the present study, chronic inflammation explained a substantial part of the association between lifecourse socioeconomic disadvantage and type 2 diabetes. Further studies should be performed to confirm these findings in population-based samples, as the Whitehall II cohort is not representative of the general population, and to examine the extent to which social inequalities attributable to chronic inflammation are reversible.

Impact of socioeconomic status on diabetes and cardiovascular risk factors: results of a large French survey

AIM

This study examined the association between deprivation and diabetes in a large French population, and evaluated the impact of deprivation on diabetes after taking in account a number of confounding factors.

METHODS

A total of 32,435 men and 16,378 women, aged 35 to 80 years, who had a health checkup at the "Centre d'Investigations Préventives et Cliniques" (IPC Centre: a preventive medical center in Paris, France), between January 2003 and December 2006, were evaluated. Socioeconomic deprivation was assessed using the EPICES score. The most deprived subjects were those in the fifth quintile of score distribution.

RESULTS

Several cardiovascular risk markers increased significantly in deprived subjects. In both genders, deprivation was associated with deleterous health status and lifestyle habits. In women, BMI, central obesity and the metabolic syndrome were associated with deprivation. The prevalence of diabetes increased with deprivation level. Compared with the first quintile of EPICES score distribution, the prevalence of diabetes was three to eight times higher in the fifth quintile. After taking into account age, and biological, clinical and lifestyle parameters, the risk of diabetes onset (odds ratio) among deprived vs. non-deprived subjects was 2.54 (95% CI: 1.99-3.24) in men and 2.2 (95% CI: 1.44-3.35) in women.

CONCLUSION

In the general French population, deprivation was associated with deleterious health status and lifestyle. Risk of diabetes increased linearly with deprivation level and, after taking into account various confounding factors, the risk of diabetes remained significantly higher among deprived subjects. Other factors such as nutrition should now be examined to explain the excess risk of diabetes among the most deprived people.

Lower educational level is a predictor of incident type 2 diabetes in European countries: the EPIC-InterAct study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide. In high-income countries, low socioeconomic status seems to be related to a high incidence of T2DM, but very little is known about the intermediate factors of this relationship. Method We performed a case-cohort study in eight Western European countries nested in the EPIC study (n = 340, 234, 3.99 million person-years of follow-up). A random sub-cohort of 16,835 individuals and a total of 12,403 incident cases of T2DM were identified. Crude and multivariate-adjusted hazard ratios (HR) were estimated for each country and pooled across countries using meta-analytical methods. Age-, gender- and country-specific relative indices of inequality (RII) were used as the measure of educational level and RII tertiles were analysed.

RESULTS

Compared with participants with a high educational level (RII tertile 1), participants with a low educational level (RII tertile 3) had a higher risk of T2DM [HR: 1.77, 95% confidence interval (CI): 1.69-1.85; P-trend < 0.01]. The HRs adjusted for physical activity, smoking status and propensity score according to macronutrient intake were very similar to the crude HR (adjusted HR: 1.67, 95% CI: 1.52-1.83 in men; HR: 1.88, 95% CI: 1.73-2.05 in women). The HRs were attenuated only when they were further adjusted for BMI (BMI-adjusted HR: 1.36, 95% CI: 1.23-1.51 in men; HR: 1.32, 95% CI: 1.20-1.45 in women).

CONCLUSION

This study demonstrates the inequalities in the risk of T2DM in Western European countries, with an inverse relationship between educational level and risk of T2DM that is only partially explained by variations in BMI.

The relationship between high blood glucose and socio-economic position in childhood and adulthood in Korea: findings from the Korean National Health and Nutrition Examination, 2007-09

BACKGROUND

Unlike the older birth cohort (1943-65), the younger birth cohort (1966-79) has enjoyed much improved standards with dramatic developments in Korea. This article investigated the relationship between socio-economic position (SEP) and risk of high blood glucose, including impaired fasting glucose (IFG) and type 2 diabetes mellitus (T2D) by birth cohort.

METHODS

Of the 11 830 persons, 9792 persons aged 30-64 years participated in National Health and Nutrition Examination Surveys. We categorized four SEP groups based on education level in childhood and adulthood within two birth cohorts. High blood glucose included IFG (n = 2594) and T2D (n = 738). Odds ratio (OR) and 95% confidence interval (CI) were estimated by logistic regression.

RESULTS

There was a significantly higher risk of high blood glucose in the younger cohort than in the older cohort. In the younger cohort, the ORs for males of declining SEP and of stable low SEP were OR: 1.50 (95% CI 1.12-2.00) and OR: 1.45 (95% CI 1.08-1.93), respectively. After adjustments, corresponding ORs were 1.47 (95% CI 1.09-1.98) and 1.54 (95% CI 1.14-2.08), respectively. In younger women, the corresponding ORs were 1.68 (95% CI 1.17-2.41) and 1.87 (95% CI 1.30-2.69), respectively; however, obesity attenuated the former relationship. For women in the older cohort, this inverse relationship was found only among those with a stable low SEP (OR 1.31, 95% CI 1.04-1.66); no significance was found after adjustments. There was no significant inverse relationship in the older cohort for men.

CONCLUSIONS

The relationship between lower SEP and elevated risk of high blood glucose was stronger in the younger birth cohort, and obesity attenuated this inverse relationship in women only.

Challenges using online surveys in a Danish population of people with type 2 diabetes

OBJECTIVES

To investigate response rates for online and paper versions of an identical questionnaire and the differences between respondents to each and between respondents and non-respondents among a population with type 2 diabetes.

METHODS

We mailed letters containing an invitation to complete an online questionnaire to 2045 individuals, followed by two reminders; the second included a paper version of the questionnaire.

RESULTS

In total, 1081 people responded to either version of the questionnaire, yielding a response rate of 54%. Compared to total respondents, respondents completing the online version were more likely to be male, better educated, and younger, and have had diabetes for a shorter period of time. Compared to non-respondents, respondents were more likely to be male and have a lower hemoglobin A1c level.

CONCLUSION

Web-based surveys are capable of delivering a substantial number of responses cost-effectively. However, disadvantages related to selection bias should be taken into account, and mixed-mode methods should be considered when surveying populations with type 2 diabetes.

Socioeconomic status and incident type 2 diabetes mellitus: data from the Women's Health Study

Objectives

We prospectively examined whether socioeconomic status (SES) predicts incident type II diabetes (diabetes), a cardiovascular risk equivalent and burgeoning public health epidemic among women.

Methods

Participants include 23,992 women with Hb_A1c levels <6% and no CVD or diabetes at baseline followed from February 1993 to March 2007. SES was measured by education and income while diabetes was self-reported.

Results

Over 12.3 years of follow-up, 1,262 women developed diabetes. In age and race adjusted models, the relative risk of diabetes decreased with increasing education (<2 years of nursing, 2 to <4 years of nursing, bachelor's degree, master's degree, and doctorate: 1.0, 0.7 [95% Confidence Interval (CI), 0.6–0.8], 0.6 (95% CI, 0.5–0.7), 0.5 (95% CI, 0.4–0.6), 0.4 (95% CI, 0.3–0.5); p_trend<0.001). Adjustment for traditional and non-traditional cardiovascular risk factors attenuated this relationship (education: p_trend = 0.96). Similar associations were observed between income categories and diabetes.

Conclusion

Advanced education and increasing income were both inversely associated with incident diabetes even in this relatively well-educated cohort. This relationship was largely explained by behavioral factors, particularly body mass index.

The influence of non-response in a population-based cohort study on type 2 diabetes evaluated by the Swedish Prescribed Drug Register

Bias due to non-response in observational studies may lead to false risk estimates. We evaluated potential selective non-response in Stockholm Diabetes Prevention Program (SDPP) using a population-based drug register. A cohort of 12,952 men and 19,416 women, aged 35-56 years, was screened for diabetes and family history of diabetes (FHD). Response rate: 79% in men and 85% in women. Of the 4,209 men and 6,916 women that were invited, 70 and 68% participated in a baseline health examination including oral glucose tolerance test. A follow-up was performed in 79% of male and 70% of female baseline participants. We used data from the prescription register to estimate absolute risks and ORs for drug-treated diabetes in the non-response/non-participation groups. At both screening and baseline steps absolute risks of drug-treated diabetes were equal in non-participants and participants. Adjusted ORs were 0.9-1.0. At follow-up, absolute risks were higher among non-participants than participants, men 6.2/4.4% and women 2.6/1.6%, adjusted ORs 1.4 (0.9-2.3) and 1.5 (0.9-2.4), suggesting selective non-participation. Further analyses of FHD, smoking, physical activity, socioeconomic position and psychological distress demonstrated no previous false risk estimates for type 2 diabetes. However, for body mass index, there were indications of overestimation in women. We conclude that bias from non-response was not present at screening or baseline steps, suggesting that diabetes prevalence and risks may be estimated from a population-based cohort study with high attendance rate such as the SDPP. However, follow-up data should be treated with some caution, since the sample may have become biased.

High prevalence of hyperglycaemia and the impact of high household income in transforming rural China

Background

The prevalence of hyperglycaemia and its association with socioeconomic factors have been well studied in developed countries, however, little is known about them in transforming rural China.

Methods

A cross-sectional study was carried out in 4 rural communities of Deqing County located in East China in 2006-07, including 4,506 subjects aged 18 to 64 years. Fasting plasma glucose (FPG) was measured. Subjects were considered to have impaired fasting glucose (IFG) if FPG was in the range from 5.6 to 6.9 mmol/L and to have diabetes mellitus (DM) if FG was 7.0 mmol/L or above.

Results

The crude prevalences of IFG and DM were 5.4% and 2.2%, respectively. The average ratio of IFG/DM was 2.5, and tended to be higher for those under the age of 35 years than older subjects. After adjustment for covariates including age (continuous), sex, BMI (continuous), smoking, alcohol drinking, and regular leisure physical activity, subjects in the high household income group had a significantly higher risk of IFG compared with the medium household income group (OR: 1.74, 95% CI: 1.11-2.72) and no significant difference in IFG was observed between the low and medium household income groups. Education and farmer occupation were not significantly associated with IFG.

Conclusions

High household income was significantly associated with an increased risk of IFG. A high ratio of IFG/DM suggests a high risk of diabetes in foreseeable future in the Chinese transforming rural communities.

Sleep duration is a potential risk factor for newly diagnosed type 2 diabetes mellitus

U-shaped patterns have been observed for the relationship between sleep duration and diabetes. In addition, prediabetes is associated with the risk of cardiovascular diseases and diabetes. However, there are few studies investigating the relationship between sleep duration and prediabetes/newly diagnosed diabetes. The aim of this study is to examine the relationship between sleep duration and prediabetes/newly diagnosed diabetes in a Taiwanese population. After excluding the subjects with a high risk of obstructive sleep apnea, those with a positive history of diabetes, or those taking hypnotic drugs, a total of 3470 adults were recruited from a health checkup center. Each subject completed a self-administrated structured questionnaire on sleep duration and lifestyle factors. Prediabetes/diabetes was defined following the definition of the American Diabetes Association. Subjects with different sleep durations were classified into short (<6.0 hours), normal (6.0∼8.49 hours), and long sleepers (≥8.5 hours). The proportion of subjects with normal glucose tolerance, prediabetes, and newly diagnosed diabetes was 71.9%, 22.9%, and 5.2%, respectively. There were significant differences in age, sex, weight, education level, body mass index, waist-to-hip ratio, systolic and diastolic blood pressure, alcohol and coffee drinking habits, family history of diabetes, and sleep duration among the 3 glycemic groups. In multinomial regression, both short and long sleepers had a higher risk of newly diagnosed diabetes; and the odds ratio were 1.55 (95% confidence interval, 1.07-2.24) and 2.83 (1.19-6.73), respectively. However, sleep duration was not found to relate to prediabetes. In conclusion, both short and long sleep durations were independently associated with newly diagnosed diabetes, but not with prediabetes.

Predictors of lifestyle intervention outcome and dropout: the SLIM study

BACKGROUND/OBJECTIVES

To evaluate the effect of a 4.1-year (range 3-6 years) lifestyle intervention according to general public health recommendations on glucose tolerance and dropout in a Dutch population with impaired glucose tolerance (IGT).

SUBJECTS/METHODS

In the Study on Lifestyle intervention and Impaired glucose tolerance Maastricht, 147 Caucasian IGT subjects were randomized to an intervention group (INT: n=74; 38 male, 36 female) and control group (CON: n=73; 37 male, 36 female). Annually, subjects underwent measurements of body weight, anthropometry, glucose tolerance (oral glucose tolerance test), insulin resistance (homeostasis model assessment-insulin resistance), maximal aerobic capacity (VO(2) max), blood lipids and blood pressure. INT received individual advice regarding a healthy diet and physical activity.

RESULTS

INT decreased their saturated fat intake, increased their carbohydrate intake (P<0.05) and VO(2) max (P=0.04) compared with CON. Body weight did not change significantly (P=0.20) between the groups. After an initial decrease, 2-h glucose levels overall increased in INT (+0.11 mmol/l), but significantly less than CON (+1.18 mmol/l; P=0.04). Diabetes incidence was lower in INT versus CON (30 versus 56%, P=0.04). Change in body weight was associated with change in 2-h glucose levels (β=0.399 mmol/l per kg, P=0.02). Dropouts had a lower aerobic fitness and socioeconomic status, and a higher body mass index (BMI) and 2-h glucose compared with non-dropouts.

CONCLUSIONS

Prolonged feasible changes in diet and physical activity prevent deterioration of glucose tolerance and reduce diabetes risk. Low socioeconomic status, low aerobic fitness and high BMI and 2-h glucose are indicative of dropout to the program.

Country of birth, socioeconomic factors, and risk factor control in patients with type 2 diabetes: a Swedish study from 25 primary health-care centres

BACKGROUND

Few large-scale studies have examined the association between sociodemographic factors and the probability of reaching the recommended levels of haemoglobin A1c (HbA(1c)) and blood lipids in patients with type 2 diabetes. The aim was to investigate whether sociodemographic characteristics of patients with type 2 diabetes affected the odds that they would reach recommended levels of blood lipids and HbA(1c).

METHODS

This study included 2912 men and 2136 women, in the age group of 35-74, with diagnosed type 2 diabetes from 25 primary health-care centres in Stockholm, Sweden. National population registers were linked to clinical data from electronic records and logistic regression was used to estimate odds ratios.

RESULTS

Less than half of the men and women with diabetes reached the recommended levels of HbA(1c). Even fewer reached the recommended levels for total cholesterol and low-density lipoprotein cholesterol. The gender differences favoured women, for HbA(1c) and men, for blood lipids. Individuals with the lowest income levels were less likely to reach the recommended level of HbA(1c). Country of birth showed that immigrants from Middle Eastern countries and other countries had lower odds of reaching the recommended levels of HbA(1c).

CONCLUSION

This study confirmed that risk factor control among patients with type 2 diabetes treated in primary health care is inadequate and that sociodemographic factors were associated with metabolic control. Future studies could include new strategies for the control of modifiable risk factors in patients with type 2 diabetes.

Gestational diabetes history may signal deprivation in women with type 2 diabetes

BACKGROUND

There is a higher prevalence of type 2 diabetes in lower income groups, particularly in women. Gestational diabetes (diabetes during pregnancy) has also been associated with lower income levels. What has not been studied is whether a past history of gestational diabetes retains an inverse association with income among women with type 2 diabetes.

METHODS

Among women with type 2 diabetes, we assessed for an association between history of gestational diabetes and lower income/lower educational attainment (multiple waves of Canadian Community Health Survey [CCHS]) through logistic regression models adjusted for age, body mass index (BMI), immigrant and marital status, smoking history, and physical activity.

RESULTS

Compared to women in the highest income group, a gestational diabetes history was 71% more likely in the lower middle income group (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.06-2.74) and nearly two times more likely in the lowest income group (OR 1.94, 95% CI 1.15-3.27). Associations with education were inconclusive. Compared to married women, single women (divorced/separated/never married) were nearly two times more likely to have a gestational diabetes history (OR 1.71, 95% CI 1.17-2.49).

CONCLUSIONS

These findings indicate that women with diabetes and past history of gestational diabetes constitute a particularly deprived group. A gestational diabetes history in women with type 2 diabetes may signal a need to assess and address material resources and social support as part of the diabetes management plan.

Life-course socioeconomic position and type 2 diabetes mellitus: The Framingham Offspring Study

Evidence is lacking on whether the duration and timing of low socioeconomic position (SEP) across a person's life course may be associated with incidence of type 2 diabetes mellitus (T2D). The authors' objectives were to investigate associations between cumulative SEP and the incidence of T2D in the Framingham Offspring Study (n = 1,893; 52% women; mean baseline age = 34 years). Pooled logistic regression analyses demonstrated that age-adjusted cumulative SEP was associated with T2D in women (for low vs. high cumulative SEP, odds ratio (OR) = 1.92, 95% confidence interval (CI): 1.08, 3.42). Age-adjusted analyses for young-adulthood SEP (7.85 for ≤12 vs. >16 years of education, OR = 2.84, 95% CI: 1.03), active professional life SEP (for laborer vs. professional/executive/supervisory/technical occupations, OR = 2.40, 95% CI: 1.05, 5.47), and social-mobility frameworks (for declining life-course SEP, OR = 2.99, 95% CI: 1.39, 6.44; for stable low vs. stable high life-course SEP, OR = 1.85, 95% CI: 1.02, 3.35) all demonstrated associations between low SEP and T2D incidence in women. No association was observed between childhood SEP and T2D in women for father's education (some high school or less vs. any postsecondary education, OR = 1.26, 95% CI: 0.72, 2.22). In men, there was little evidence of associations between life-course SEP and T2D incidence. These findings suggest that cumulative SEP is inversely associated with incidence of T2D in women, and that this association may be primarily due to the women's educational levels and occupations.

Bypassing the selection rule in choosing controls for a case-control study

OBJECTIVES

It has been argued that in case-control studies, controls should be drawn from the base population that gives rise to the cases. In designing a study of occupational injury and risks arising from long-term illness and prescribed medication, we lacked data on subjects' occupation, without which employed cases (typically in manual occupations) would be compared with controls from the general population, including the unemployed and a higher proportion of white-collar professions. Collecting the missing data on occupation would be costly. We estimated the potential for bias if the selection rule were ignored.

METHODS

We obtained published estimates of the frequencies of several exposures of interest (diabetes, mental health problems, asthma, coronary heart disease) in the general population, and of the relative risks of these diseases in unemployed versus employed individuals and in manual versus non-manual occupations. From these we computed the degree of over- or underestimation of exposure frequencies and exposure ORs if controls were selected from the general population.

RESULTS

The potential bias in the OR was estimated as likely to fall between an underestimation of 14% and an overestimation of 36.7% (95th centiles). In fewer than 6% of simulations did the error exceed 30%, and in none did it reach 50%.

CONCLUSIONS

For the purposes of this study, in which we were interested only in substantial increases in risk, the potential for selection bias was judged acceptable. The rule that controls should come from the same base population as cases can justifiably be broken, at least in some circumstances.

Impact of early psychosocial factors (childhood socioeconomic factors and adversities) on future risk of type 2 diabetes, metabolic disturbances and obesity: a systematic review

Background

Psychological factors and socioeconomic status (SES) have a notable impact on health disparities, including type 2 diabetes risk. However, the link between childhood psychosocial factors, such as childhood adversities or parental SES, and metabolic disturbances is less well established. In addition, the lifetime perspective including adult socioeconomic factors remains of further interest.

We carried out a systematic review with the main question if there is evidence in population- or community-based studies that childhood adversities (like neglect, traumata and deprivation) have considerable impact on type 2 diabetes incidence and other metabolic disturbances. Also, parental SES was included in the search as risk factor for both, diabetes and adverse childhood experiences. Finally, we assumed that obesity might be a mediator for the association of childhood adversities with diabetes incidence. Therefore, we carried out a second review on obesity, applying a similar search strategy.

Methods

Two systematic reviews were carried out. Longitudinal, population- or community-based studies were included if they contained data on psychosocial factors in childhood and either diabetes incidence or obesity risk.

Results

We included ten studies comprising a total of 200,381 individuals. Eight out of ten studies indicated that low parental status was associated with type 2 diabetes incidence or the development of metabolic abnormalities. Adjustment for adult SES and obesity tended to attenuate the childhood SES-attributable risk but the association remained. For obesity, eleven studies were included with a total sample size of 70,420 participants. Four out of eleven studies observed an independent association of low childhood SES on the risk for overweight and obesity later in life.

Conclusions

Taken together, there is evidence that childhood SES is associated with type 2 diabetes and obesity in later life. The database on the role of psychological factors such as traumata and childhood adversities for the future risk of type 2 diabetes or obesity is too small to draw conclusions. Thus, more population-based longitudinal studies and international standards to assess psychosocial factors are needed to clarify the mechanisms leading to the observed health disparities.

Socioeconomic position, gender, health behaviours and biomarkers of cardiovascular disease and diabetes

Socio-economic gradients in cardiovascular disease (CVD) and diabetes have been found throughout the developed world and there is some evidence to suggest that these gradients may be steeper for women. Research on social gradients in biological risk factors for CVD and diabetes has received less attention and we do not know the extent to which gradients in biomarkers vary for men and women. We examined the associations between two indicators of socio-economic position (education and household income) and biomarkers of diabetes and cardiovascular disease (CVD) for men and women in a national, population-based study of 11,247 Australian adults. Multi-level linear regression was used to assess associations between education and income and glucose tolerance, dyslipidaemia, blood pressure (BP) and waist circumference before and after adjustment for behaviours (diet, smoking, physical activity, TV viewing time, and alcohol use). Measures of glucose tolerance included fasting plasma glucose and insulin and the results of a glucose tolerance test (2 h glucose) with higher levels of each indicating poorer glucose tolerance. Triglycerides and High Density Lipoprotein (HDL) Cholesterol were used as measures of dyslipidaemia with higher levels of the former and lower levels of the later being associated with CVD risk. Lower education and low income were associated with higher levels of fasting insulin, triglycerides and waist circumference in women. Women with low education had higher systolic and diastolic BP and low income women had higher 2 h glucose and lower HDL cholesterol. With only one exception (low income and systolic BP), all of these estimates were reduced by more than 20% when behavioural risk factors were included. Men with lower education had higher fasting plasma glucose, 2 h glucose, waist circumference and systolic BP and, with the exception of waist circumference, all of these estimates were reduced when health behaviours were included in the models. While low income was associated with higher levels of 2-h glucose and triglycerides it was also associated with better biomarker profiles including lower insulin, waist circumference and diastolic BP. We conclude that low socio-economic position is more consistently associated with a worse profile of biomarkers for CVD and diabetes for women.

Type 2 diabetes in Canada: concentration of risk among most disadvantaged men but inverse social gradient across groups in women

AIMS

To assess sex-specific associations of educational and income levels with Type 2 diabetes mellitus.

METHODS

Logistic regression analyses (Canadian Community Health Survey, cross-sectional) adjusted for ethnicity, immigration, urban/rural, overweight/obesity, physical inactivity, smoking, chronic conditions and regular physician.

RESULTS

Compared to women with some post-secondary education, Type 2 diabetes was more likely in both high school graduates without post-secondary education [odds ratio (OR) 1.27, 95% confidence interval (CI) 1.07-1.51] and high school non-completers (OR 1.73, 95% CI 1.47-2.04); among men, definitive conclusions in high school graduates without post-secondary education could not be drawn (OR 0.93, 95% CI 0.78-1.12), but Type 2 diabetes was more likely in high school non-completers (OR 1.26, 95% CI 1.08-1.48). Compared to women with the highest income, Type 2 diabetes was three times more likely in the lowest income group (OR 2.90, 95% CI 2.25-3.73), 2.53 times more likely in the low middle income group (OR 2.53, 95% CI 1.98-3.24) and 55% more likely in the high middle income group (OR 1.55, 95% CI 1.20-2.01). Among men, Type 2 diabetes was approximately 40% more likely in both the lowest (OR 1.41, 95% CI 1.10-1.80) and low middle income groups (OR 1.39, 95% CI 1.12-1.71); definitive conclusions in the high middle income group could not be drawn (OR 1.05, 95% CI 0.87-1.28).

CONCLUSIONS

In women, Type 2 diabetes increased monotonically with lower educational and income levels; in men, Type 2 diabetes was concentrated in the least educated and least affluent. Our findings support the need for policies and practices that lower diabetes risk among the most disadvantaged women and men and moderately disadvantaged women.

Socioeconomic status and incidence of type 2 diabetes: results from the Black Women's Health Study

The authors examined the relation between individual and neighborhood socioeconomic status (SES) and type 2 diabetes incidence among African-American women in the prospective Black Women's Health Study. Participants have completed mailed biennial follow-up questionnaires since 1995. US Census block group characteristics were used to measure neighborhood SES. Incidence rate ratios were estimated in clustered survival regression models. During 12 years of follow-up of 46,382 participants aged 30-69 years, 3,833 new cases of type 2 diabetes occurred. In models that included both individual and neighborhood SES factors, incidence rate ratios were 1.28 (95% confidence interval: 1.15, 1.43) for < or = 12 years of education relative to > or = 17 years, 1.57 (95% confidence interval: 1.30, 1.90) for household income <$15,000 relative to >$100,000, and 1.65 (95% confidence interval: 1.46, 1.85) for lowest quintile of neighborhood SES relative to highest. The associations were attenuated after adjustment for body mass index, suggesting it is the key intermediate factor in the pathway between SES and diabetes. The association of neighborhood SES with diabetes incidence was present even among women who were more educated and had a higher family income. Efforts to reduce the alarming rate of diabetes in African-American women must focus on both individual lifestyle changes and structural changes in disadvantaged neighborhoods.

Diabetes in African American youth: prevalence, incidence, and clinical characteristics: the SEARCH for Diabetes in Youth Study

OBJECTIVE

To report the prevalence and incidence of type 1 and type 2 diabetes among African American youth and to describe demographic, clinical, and behavioral characteristics.

RESEARCH DESIGN AND METHODS

Data from the SEARCH for Diabetes in Youth Study, a population-based, multicenter observational study of youth with clinically diagnosed diabetes aged 0-19 years, were used to estimate the prevalence for calendar year 2001 (692 cases) and incidence based on 748 African American case subjects diagnosed in 2002-2005. Characteristics of these youth were obtained during a research visit for 436 African American youth with type 1 diabetes and 212 African American youth with type 2 diabetes.

RESULTS

Among African American youth aged 0-9 years, prevalence (per 1,000) of type 1 diabetes was 0.57 (95% CI 0.47-0.69) and for those aged 10-19 years 2.04 (1.85-2.26). Among African American youth aged 0-9 years, annual type 1 diabetes incidence (per 100,000) was 15.7 (13.7-17.9) and for those aged 10-19 years 15.7 (13.8-17.8). A1C was >or=9.5% among 50% of youth with type 1 diabetes aged >or=15 years. Across age-groups and sex, 44.7% of African American youth with type 1 diabetes were overweight or obese. Among African American youth aged 10-19 years, prevalence (per 1,000) of type 2 diabetes was 1.06 (0.93-1.22) and annual incidence (per 100,000) was 19.0 (16.9-21.3). About 60% of African American youth with type 2 diabetes had an annual household income of <$25,000. Among those aged >or=15 years, 27.5% had an A1C >or=9.5%, 22.5% had high blood pressure, and, across subgroups of age and sex, >90% were overweight or obese.

CONCLUSIONS

Type 1 diabetes presents a serious burden among African American youth aged <10 years, and African American adolescents are impacted substantially by both type 1 and type 2 diabetes.

The impact of education on risk factors and the occurrence of multimorbidity in the EPIC-Heidelberg cohort

Background

In aging populations, the prevalence of multimorbidity is high, and the role of socioeconomic status and its correlates is not well described. Thus, we investigated the association between educational attainment and multimorbidity in a prospective cohort study, taking also into account intermediate factors that could explain such associations.

Methods

We included 13,781 participants of the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC), who were 50–75 years at the end of follow-up. Information on diet and lifestyle was collected at recruitment (1994–1998). During a median follow-up of 8.7 years, information on chronic conditions and death were collected.

Results

Overall, the prevalence of multimorbidity (>= 2 concurrent chronic diseases) was 67.3%. Compared to the highest educational category, the lowest was statistically significantly associated with increased odds of multimorbidity in men (OR = 1.43; 95% CI 1.28–1.61) and women (OR = 1.33; 95% CI 1.18–1.57). After adjustment, the positive associations were attenuated (men: OR = 1.28; 95% CI 1.12–1.46; women: OR = 1.16; 95% CI 0.99–1.36). Increasing BMI was more strongly than smoking status an intermediate factor in the association between education and multimorbidity.

Conclusion

In this German population, the prevalence of multimorbidity is high and is significantly associated with educational level. Increasing BMI is the most important predictor of this association. However, even the fully adjusted model, i.e. considering also other known risk factors for chronic diseases, could not entirely explain socio-economic inequalities in multimorbidity. Educational level should be considered in the development and implementation of prevention strategies of multimorbidity.

Adult education and child mortality in India: the influence of caste, household wealth, and urbanization

BACKGROUND

Although socioeconomic position is generally found to be related to health, the associations can be different for different measures of socioeconomic position. We examined the association between adult education and child mortality, and the influence of other socioeconomic markers (caste, household wealth, and urbanization) on this association.

METHODS

Data were drawn from the 1998-1999 Indian National Family Health Survey, conducted in 26 states and comprising 66,367 children age 5 years or under. Adult education, for the head of household and spouse, was categorized into 0, 1-8, and 9 or more years of schooling. We used logistic regression to estimate associations between education and child mortality in analysis adjusted for other socioeconomic markers. Effect modification by caste, household wealth, and urbanization was assessed by fitting an interaction term with education.

RESULTS

Compared with those who had no education, 9 or more years of education for the head of household and for the spouse were associated with lower child mortality (odds ratio [OR] = 0.54; 95% confidence interval [CI] = 0.48-0.62 and OR = 0.44; 95% CI = 0.36-0.54, respectively) in analyses adjusted for age, sex, and state of residence. Further adjustments for caste and urbanization attenuated these associations slightly; when adjustments were made for household wealth the associations were attenuated more substantially. Nevertheless, in fully adjusted models, 9 or more years of education for the head of household (OR = 0.81; 95% CI = 0.70-0.93) and the spouse (OR = 0.75; 95% CI = 0.60-0.94) remained associated with lower child mortality. There was no effect modification of this association by caste, household wealth, and urbanization.

CONCLUSION

Adult education has a protective association with child mortality in India. Caste, household wealth, and urbanization do not modify or completely attenuate this association.