Life changes, locus of control and metabolic syndrome precursors in adolescents and young adults: a three-year follow-up

Association between low internal health locus of control, psychological distress and insulin resistance. An exploratory study

AIM

To assess the hypothesis that low internal health locus of control (IHLC) and psychological distress (PD) are associated with insulin resistance.

MATERIALS AND METHODS

In 2002-2005, a random population sample of 2,816 men and women aged 30-74 years participated (76%) in two municipalities in southwestern Sweden. This study included 2,439 participants without previously known diabetes or cardiovascular disease. IHLC was measured by a global scale and PD was measured by the 12-item General Health Questionnaire. Insulin resistance was estimated using HOMA-ir. General linear models were used to estimate differences in HOMA-ir between groups with low IHLC, PD, and both low IHLC and PD, respectively.

RESULTS

Five per cent (n = 138) had both PD and low IHLC, 62 per cent of participants (n = 1509) had neither low IHLC nor PD, 18 per cent (n = 432) had PD, and 15 per cent (n = 360) low IHLC. Participants with both low IHLC and PD had significantly higher HOMA-ir than participants with neither low IHLC nor PD (Δ = 24.8%, 95%CI: 12.0-38.9), also in the fully adjusted model (Δ = 11.8%, 95%CI: 1.5-23.0). Participants with PD had significantly higher HOMA-ir (Δ = 12%, 95%CI: 5.7-18.7), but the significance was lost when BMI was included in the model (Δ = 5.3%, 95%CI:0.0-10.8). Similarly, participants with low IHLC had significantly higher HOMA-ir (Δ = 10.1%, 95%CI: 3.5-17.0) but the significance was lost in the fully adjusted model (Δ = 3.5%, 95%CI: -1.9-9.3).

CONCLUSIONS

Internal health locus of control (IHLC) and psychological distress (PD) were associated with insulin resistance. Especially individuals with both PD and low IHLC may need special attention.

Psychometric properties of the Weight Locus of Control Scale (MWLCS): study with Spanish individuals of different anthropometric nutritional status

INTRODUCTION

The Multidimensional Weight Locus of Control Scale (MWLCS) measures a person's beliefs regarding the locus of control or lack of locus of control over his/her body weight.

PURPOSE

We aim to evaluate the factorial structure and psychometric properties of the MWLCS with Spanish normal weight, overweight and obese samples.

METHODS

The research was carried out in two different studies. The first included a sample of 140 normal weight participants, selected out of a 274 sample recruited with an online survey. Study 2 was carried out in a sample of 633 participants recruited from the PREDIMED-Plus study. Out of them, 558 participants fulfilled the weight criteria and were categorized into: overweight (BMI 25 - < 29.99; N = 170), obese class I (BMI 30 - < 34.99; N = 266), and obese class II (BMI 35 - < 39.99; N = 122). Exploratory (EFA) and confirmatory (CFA) factor analyses were used to evaluate the factor structure of the MWLCS, and reliabilities and Spearman's correlations were estimated. Invariance measurement was tested across the three subgroups of weight in Study 2.

RESULTS

A three-factor structure indicating weight locus of control factors (internal, chance, and powerful others) was supported, both via EFA in the normal weight sample and CFA in the overweight and obese samples. In the normal weight sample, the powerful others dimension was positively related to BMI and the dimensions of the Dutch Eating Behaviors Questionnaire. Additionally, the scale showed evidence of scalar invariance across the groups with different weight conditions.

CONCLUSIONS

This scale seems to be a psychometrically appropriate instrument and its use is highly recommended when designing interventions for overweight or obese individuals.

LEVEL OF EVIDENCE

Level V, descriptive study.

Gender, stressful life events and interactions with sleep: a systematic review of determinants of adiposity in young people

OBJECTIVES

Overweight and obesity among young people are high and rising. Social stressors and sleep are independently associated with obesity, but are rarely studied together or examined for gender-specific effects. The literature regarding adolescent populations is especially lacking. This review assesses whether experiencing stressful life events results in greater adiposity in young women and young men compared with those who do not experience stressful life events, and whether the relationship is modified by sleep problems.

DESIGN

We systematically searched six bibliometric databases (Web of Science, Embase Ovid, PsycINFO, CINHAL, PubMed, ProQuest Dissertations) supplemented by hand searches. Longitudinal prospective studies or reviews were eligible for inclusion when they examined gender-specific changes in adiposity in young adults (age 13-18 years) as a function of stressful life event alone or in combination with sleep problems.

RESULTS

We found one study eligible for inclusion reporting mixed impact of stressful life events on body mass index (BMI) between genders. The study assessed specific life events and showed significantly lower BMI at follow-up among young men who experienced a residence change, but significantly higher BMI among young women who experienced setting up a family and who reported internal locus of control.

CONCLUSIONS

Despite ample research on social stressors or sleep problems and weight, we still know little about the role of stressful life events, or combined effects with sleep, on obesity risk in adolescents from a gender perspective. Existing evidence suggests specific life events affect weight differently between the genders. Robust, high-quality longitudinal studies to decipher this dual burden on obesity during adolescence should be prioritised, as firm conclusions remain elusive.

Relationships between 24-hour urinary free cortisol concentrations and metabolic syndrome in obese children

CONTEXT

Clinical features of Metabolic Syndrome (MetS) and Cushing's Syndrome are similar, suggesting a pathogenetic role of hypothalamus-pituitary-adrenal axis in MetS.

OBJECTIVE

The aim of the study was to determine whether MetS diagnosis and specific clusters of MetS components (waist circumference, dyslipidemia, hypertension, and impaired glucose metabolism) are associated with serum cortisol (SC) or 24-h urinary free cortisol (UFC) levels.

DESIGN AND SETTING

We conducted cross-sectional analyses of data from our obesity cohort. We studied 264 obese children (age, 11.0 ± 2.8 years; male, 48%; BMI, 28.2 ± 5.4 kg/m(2)). We examined UFC, SC, homeostasis model assessment (HOMA), and features of MetS (waist circumference, blood pressure, fasting lipids, and glucose).

RESULTS

Slightly increased UFC concentrations were measured in 30.7% of the children. Obese children with MetS had significantly (P = .003) higher UFC levels compared with obese children without MetS. Girls demonstrated significantly higher UFC concentrations compared with boys independent of pubertal stage. UFC and SC levels were significantly related to features of MetS, but the associations were stronger for UFC. In multivariate analyses adjusted for age, sex, and body mass index, none of the features of MetS but HOMA index was correlated with UFC, whereas SC demonstrated no significant association to any parameter of MetS or HOMA.

CONCLUSIONS

Our findings support the hypothesis that changes in the hypothalamus-pituitary-adrenal axis are related to MetS in obesity. UFC seems to be a suitable marker for this relationship. Norm values for UFC adapted to obese children may help to avoid unnecessary dexamethasone suppression tests.

Stress and paediatric obesity: what we know and where to go

Childhood obesity is a public health epidemic and is associated with substantial negative physical and psychosocial health consequences. Stress is thought to be one contributor to the development and maintenance of obesity in children and adolescents, yet the linkage between stress and paediatric obesity is a poorly understood phenomenon. This paper furthers the understanding of stress in the context of paediatric obesity by firstly presenting a focused review of what is known about links between chronic and acute stress and paediatric obesity risk and then synthesizing important areas from the literature. These critical areas of focus include the following: (1) physiological stress reactivity; (2) stress-induced eating; (3) stress and physical activity; (4) parent and family influences; and (5) stress in at-risk populations. This review is geared toward facilitating future research on the stress-obesity connection in youth.

Prevalence of endocrine disorders in morbidly obese patients and the effects of bariatric surgery on endocrine and metabolic parameters

BACKGROUND

Several endocrine abnormalities, including hypothyroidism and Cushing's syndrome (CS), are considered as causative factors of obesity. The aim of this study was to evaluate the prevalence of endocrine disorders and obesity-associated co-morbidities, as well as the impact of substantial weight loss.

METHODS

Screening was performed in 433 consecutive morbidly obese patients (age 41 ± 12 years; BMI 47 ± 6.9 kg/m(2); women 76%). A 1-mg dexamethasone suppression test (1-mg DST) was conducted to exclude CS, and thyrotropin (TSH) was measured to exclude hypothyroidism. Insulin sensitivity was estimated from oral glucose tolerance tests employing the Clamp-like index. Examinations were carried out at baseline, as well as at 6 and 12 months postoperatively.

RESULTS

The prevalence of CS was below 0.6%. Before surgery, TSH was elevated compared to an age- and sex-matched normal weight control group (2.4 ± 1.2 vs. 1.5 ± 0.7 μU/ml; p < 0.001). The NCEP criteria of metabolic syndrome (MetS) were fulfilled by 39.5% of the patients. Impaired glucose tolerance and diabetes mellitus were observed in 23.5% and 22.6%, respectively. Seventy-two percent were insulin resistant. During follow-up, weight (BMI 47 ± 6.9 vs. 36 ± 6.4 vs. 32 ± 6.6 kg/m(2); p < 0.001) and TSH decreased significantly (2.4 ± 1.2 vs. 1.8 ± 1.0 vs. 1.8 ± 1.0 μU/ml; p < 0.001). Serum cortisol was higher in the MetS(+)-group compared to the MetS(-)-group (15.0 ± 6.3 vs. 13.5 ± 6.3 μg/dl; p = 0.003).

CONCLUSIONS

CS appears to be a rare cause of morbid obesity. Normalization of slightly elevated thyrotropin after weight loss suggests that obesity causes TSH elevation rather than the reverse.

Cortisol is negatively associated with insulin sensitivity in overweight Latino youth

CONTEXT AND OBJECTIVE

The purpose of the present study was to investigate the cross-sectional and longitudinal associations of serum morning cortisol and aspects of insulin action in Latino children and adolescents (8-13 yr) at risk for type 2 diabetes.

DESIGN AND PARTICIPANTS

The present study includes a cross-sectional analysis in 211 participants and a longitudinal analysis in a subset of 143 participants.

RESULTS

At baseline, cortisol was negatively associated with fasting glucose (r = 0.23; P < 0.01), β-cell function (disposition index, r = -0.24; P < 0.05), and acute insulin response to glucose (r = -0.27; P < 0.05). Baseline cortisol was also significantly related to the change in insulin sensitivity over 1 yr (r = -0.23; P < 0.05). These results did not differ by Tanner stage or sex.

CONCLUSIONS

Cortisol contributes to the reduction in insulin sensitivity at an early age in Latino children and adolescents. Specifically, cortisol is negatively associated with potential compensatory mechanisms for insulin resistance, such as increased β-cell function and increased insulin release to a glucose challenge, by exacerbating the progression toward insulin resistance in this population. The results underline the relevance of glucocorticoid reduction for the prevention of metabolic disease in Latino children and adolescents.

Factor analysis of metabolic syndrome components in the Coronary Artery Risk Development in Young Adults (CARDIA) study: examination of factors by race-sex groups and across time

PURPOSE

This study tests hypotheses of one-, two-, three-, and four-factor models of metabolic syndrome (MetS) components and assesses the consistency and fit of the factor models 10 years later using confirmatory factor analysis in a large biracial sample of men and women.

METHODS

With the use of data from the baseline and year-10 exams of the Coronary Artery Risk Development in Young Adults Study, confirmatory factor analysis was performed overall and for race- and sex-specific groups for one-, two-, three-, and four-factor MetS models in 3403 white and black men and women at baseline and in 2532 white and black men and women 10 years later. Metabolic risk variables used in the factor analysis were insulin resistance (HOMA-IR), fasting glucose, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, waist circumference, waist-hip ratio, triceps skinfolds, and uric acid.

RESULTS

Three- and four-factor models of MetS achieved excellent fits of the data, ranging from 0.92 to 0.96 for race- and sex-specific models and from the baseline to year-10 exams.

CONCLUSIONS

The results suggest that MetS factors are consistent across time and race-sex groups. When investigating the MetS, it is necessary to evaluate race-sex groups.

Childhood emotional problems and self-perceptions predict weight gain in a longitudinal regression model

BACKGROUND

Obesity and weight gain are correlated with psychological ill health. We predicted that childhood emotional problems and self-perceptions predict weight gain into adulthood.

METHODS

Data on around 6,500 individuals was taken from the 1970 Birth Cohort Study. This sample was a representative sample of individuals born in the UK in one week in 1970. Body mass index was measured by a trained nurse at the age of 10 years, and self-reported at age 30 years. Childhood emotional problems were indexed using the Rutter B scale and self-report. Self-esteem was measured using the LAWSEQ questionnaire, whilst the CARALOC scale was used to measure locus of control.

RESULTS

Controlling for childhood body mass index, parental body mass index, and social class, childhood emotional problems as measured by the Rutter scale predicted weight gain in women only (least squares regression N = 3,359; coefficient 0.004; P = 0.032). Using the same methods, childhood self-esteem predicted weight gain in both men and women (N = 6,526; coefficient 0.023; P < 0.001), although the effect was stronger in women. An external locus of control predicted weight gain in both men and women (N = 6,522; coefficient 0.022; P < 0.001).

CONCLUSION

Emotional problems, low self-esteem and an external locus of control in childhood predict weight gain into adulthood. This has important clinical implications as it highlights a direction for early intervention strategies that may contribute to efforts to combat the current obesity epidemic.

Association between the metabolic syndrome and serum cortisol in overweight Latino youth

OBJECTIVE

The purpose of this report is to investigate the associations between metabolic syndrome (MS) and levels of morning serum cortisol in a cohort of overweight Latino youth.

DESIGN

Subjects were 205 overweight, Latino youth (age 8-13 yr, body mass index percentile > 85, family history positive for type 2 diabetes). Measures included body composition by dual-energy x-ray absorptiometry, intraabdominal adipose tissue (IAAT) by magnetic resonance imaging, insulin sensitivity by frequently sampled iv glucose tolerance test/minimal model, fasting lipids, and serum cortisol.

RESULTS

Children with MS had higher body mass index percentile, total body fat mass, and IAAT and lower insulin sensitivity than those without MS. Children with MS had higher morning serum cortisol levels, whether unadjusted (10.1 +/- 3.7 vs. 9.0 +/- 2.8 microg/dl, P < 0.05) or after adjusting for age, gender, total body fat and lean tissue mass, and insulin sensitivity (10.4 +/- 0.4 vs. 8.9 +/- 0.3 microg/dl, P < 0.01). Increasing number of features of MS was associated with higher cortisol levels, after adjusting for covariates (P = 0.001). Among individual features of MS, systolic blood pressure had the strongest relationship with adjusted cortisol level (r = 0.34; P < 0.001), followed by diastolic blood pressure and fasting plasma glucose (both r = 0.23; P < 0.01). IAAT was associated with cortisol (r = 0.16; P < 0.05), whereas high-density lipoprotein, triglycerides, and waist circumference were not.

CONCLUSIONS

In overweight, Latino youth, MS is associated with higher morning serum cortisol levels, independent of body fat and insulin sensitivity. More studies are needed to investigate the role of relative hypercortisolism and chronic stress in obesity-related metabolic disorders in children.

Defining the metabolic syndrome in children and adolescents: will the real definition please stand up?

OBJECTIVES

To review the use of definitions of the metabolic syndrome in studies of children and adolescents and to review results from studies that used factor analysis to examine structure among cardiometabolic variables.

STUDY DESIGN

Literature review.

RESULTS

In 27 publications, authors used 40 unique definitions of the metabolic syndrome. Most of these definitions were adaptations of the adult definition developed by the National Cholesterol Education Program. In 11 studies that used exploratory factor analysis, the number of components ranged from 5 to 19, and the number of factors identified ranged from 1 to 5.

CONCLUSIONS

The use of multiple definitions of the metabolic syndrome argues strongly for the development of a standard pediatric definition.

Is there a single underlying factor for the metabolic syndrome in adolescents? A confirmatory factor analysis

OBJECTIVE

The lack of a universally applicable model for the metabolic syndrome in the pediatric population makes it difficult to define this syndrome and compare its prevalence across studies and diverse populations. We sought to assess whether a single underlying factor could represent the metabolic syndrome in adolescents.

RESEARCH DESIGN AND METHODS

Using data from the National Health and Nutrition Examination Survey (1999-2002), we conducted a confirmatory factor analysis to assess the validity of waist circumference, triglycerides, fasting insulin, and systolic blood pressure (SBP) as potential phenotypic traits for the metabolic syndrome in adolescents aged 12-17 years (n = 1,262). A multiple-group approach was used to test the invariance in factor loadings across sex and race/ethnicity.

RESULTS

The estimates of factor loadings for the total sample were 0.76, 0.46, 0.81, and 0.42 for waist circumference, triglycerides, fasting insulin, and SBP, respectively. The goodness-of-fit indexes were adequate for the total sample (comparative fit index, 0.99; standardized root mean square residual, 0.02), Caucasian boys (1.0; 0.01), African-American boys (0.99; 0.03), Mexican-American boys (1.0; 0.01), Mexican-American girls (1.0; 0.01), and Caucasian girls (0.95; 0.04) and acceptable for African-American girls (0.94; 0.05). There were no significant differences in factor loadings of the four measured variables between boys and girls and among the three racial or ethnic subgroups.

CONCLUSIONS

The metabolic syndrome as a single underlying factor for the four simple phenotypic traits may be plausible in adolescents. The proposed model appears to be generalizable across sex and race/ethnicity.

Psychological underpinnings of metabolic syndrome

Metabolic syndrome (MS) is more common among socio-economically disadvantaged individuals and is associated with certain risky lifestyle practices. MS also appears to be triggered by adverse social circumstances and chronic stress. The present paper reviews accumulating evidence to imply that individuals who have certain personality and behaviour traits are particularly predisposed to develop MS, and brings together theories that relate to possible psychological mechanisms underlying MS. It considers how such factors might interact causally to encourage the development of MS. As part of the EU-funded LIPGENE Integrated Project, multi-level modelling will be undertaken to explore potential pathways to MS, taking into consideration the interplay between a range of psycho-social, demographic, cultural and lifestyle factors thought to contribute to the development of MS. Data will be gathered for this purpose from a representative sample of >50-year-olds living in Britain (n 1000) and Portugal (n 500). It is anticipated that this information will assist in the development and targetting of future intervention to prevent and treat MS in the normal population.

Burden of psychosocial adversity and vulnerability in middle age: associations with biobehavioral risk factors and quality of life

OBJECTIVES

Numerous psychosocial factors are associated with disease risk. This study investigated the possibility that a combination of chronic stress from exposure to multiple sources and absence of protective psychosocial resources would be related to heightened emotional distress, health risk behavior, biological risk factors, and impaired quality of life, independently of socioeconomic position (SEP).

MATERIALS AND METHODS

Data were analyzed from 227 men and women aged 47 to 59 years from the Whitehall II epidemiological cohort. A psychosocial adversity and vulnerability index (PAVIX) was constructed from high scores on measures of job demands, neighborhood stress, and financial strain, low emotional support, limited social networks, low active coping, and low sense of control.

RESULTS

The measures making up the PAVIX were relatively independent of one another. Scores on the PAVIX were greater in lower SEP participants, and in single, separated, or divorced than married participants. The PAVIX was positively associated with psychological distress, depression, hopelessness, sleep problems, hostility, low self-esteem and loneliness, independently of age, sex, SEP, and marital status. There were no associations with health behaviors, but relationships were observed with glycohemoglobin, plasma fibrinogen, plasma viscosity, and body mass (women), that were again independent of covariates. Individuals with high PAVIX scores also reported impaired health-related quality of life.

DISCUSSION

The accumulated burden of life stress coupled with limited protective psychosocial resources is associated with adverse psychological, biological, and quality of life outcomes. This integrated approach to the investigation of psychosocial factors may prove valuable in understanding etiological processes.

Psychosocial and socioeconomic factors associated with glycated hemoglobin in nondiabetic middle-aged men and women

The authors tested associations between glycated hemoglobin (HbA1c; an index of glucose homeostasis and an indicator of cardiovascular disease risk in nondiabetic populations) and socioeconomic status (defined by grade of employment) and psychosocial factors in 234 British civil servants. HbA1c concentration was inversely related to grade of employment. Higher HbA1c was associated with greater waist-hip ratio, lower control at work, lower internal locus of control, lower active coping, and lower social support. Control at work, internal and chance locus of control, and active coping were also related to socioeconomic status. The association of social support but not other psychosocial factors with HbA1c was independent of socioeconomic status. HbA1c may complement measures of the metabolic syndrome and insulin resistance in studies of psychosocial factors in cardiovascular disease risk.

Ten-year review of rating scales. III: scales assessing suicidality, cognitive style, and self-esteem

OBJECTIVE

This is the third article in a series of 10-year reviews of rating scales. Here, the authors review scales that are useful in tapping the affective disturbances experienced with various psychiatric disorders, including suicidality, cognitive style, and self-esteem.

METHOD

The authors sampled articles incorporating these constructs over the past 25 years and selected scales with established uses or new development. Those presented here have adequate psychometric properties and high utility for efficiently elucidating youths' functioning, plus either wide literature citations or a special niche.

RESULTS

These scales were developed bimodally. Many were developed in the 1980s when internalizing disorders were elucidated, but there has been a resurgence of interest in these constructs. Scales assessing suicidality have clear constructs, whereas scales of cognitive style demonstrate deficits in developmental relevance, and scales of self-esteem suffer from lax constructs.

CONCLUSIONS

The constructs underlying these scales tap core symptoms of internalizing disorders, mediate the expression of affective disturbances associated with various disorders, and depict the impairments resulting from these disorders. Overall, the psychometrics of these scales are adequate. These scales provide a broader representation of youths' functioning than that conveyed with diagnostic scales alone.

Metabolic control and psychological sense of control in women with diabetes mellitus. Alternative considerations of the relationship

PURPOSE

Identifying psychological strategies to buffer the adverse outcomes in people with diabetes mellitus (DM) remains a priority for many health professionals. While 'locus of control' (LOC) has been repeatedly investigated to this end, research findings are contradictory. The development of more complex appraisals of psychological control, and the utilization of control inventories deriving from such analyses, presents a way forward from such contradictions.

METHODS

Employing such a measure, this study examines the relationship between metabolic control and psychological sense of control in 96 women with DM.

RESULTS

Optimal metabolic control is significantly associated with overall sense of control, while poor metabolic control was significantly associated with experiences of loss of psychological control and feelings of inadequacy. Furthermore, poor metabolic control was significantly associated with reduced control in the specific domains of interpersonal relationships and bodily functions.

CONCLUSIONS

Multidimensional control inventories enable a more complex appraisal of the relationship between metabolic control and psychological control, and in doing so, provide a way forward from problems arising from reliance on LOC constructs. Interventions for DM management relying on aspects of psychological control need to target domains beyond traditional issues of self and bodily functions.