Factor Analysis of Cardiometabolic Risk Factors Clustering in Children and Adolescents

Cardiometabolic risk factor clustering in persons with spinal cord injury: A principal component analysis approach

CONTEXT/OBJECTIVE

To identify cardiometabolic (CM) measurements that cluster to confer increased cardiovascular disease (CVD) risk using principal component analysis (PCA) in a cohort of chronic spinal cord injury (SCI) and healthy non-SCI individuals.

APPROACH

A cross-sectional study was performed in ninety-eight non-ambulatory men with chronic SCI and fifty-one healthy non-SCI individuals (ambulatory comparison group). Fasting blood samples were obtained for the following CM biomarkers: lipid, lipoprotein particle, fasting glucose and insulin concentrations, leptin, adiponectin, and markers of inflammation. Total and central adiposity [total body fat (TBF) percent and visceral adipose tissue (VAT) percent, respectively] were obtained by dual x-ray absorptiometry (DXA). A PCA was used to identify the CM outcome measurements that cluster to confer CVD risk in SCI and non-SCI cohorts.

RESULTS

Using PCA, six factor-components (FC) were extracted, explaining 77% and 82% of the total variance in the SCI and non-SCI cohorts, respectively. In both groups, FC-1 was primarily composed of lipoprotein particle concentration variables. TBF and VAT were included in FC-2 in the SCI group, but not the non-SCI group. In the SCI cohort, logistic regression analysis results revealed that for every unit increase in the FC-1 standardized score generated from the statistical software during the PCA, there is a 216% increased risk of MetS (P = 0.001), a 209% increased risk of a 10-yr. FRS ≥ 10% (P = 0.001), and a 92% increase in the risk of HOMA2-IR ≥ 2.05 (P = 0.01).

CONCLUSION

Application of PCA identified 6-FC models for the SCI and non-SCI groups. The clustering of variables into the respective models varied considerably between the cohorts, indicating that CM outcomes may play a differential role on their conferring CVD-risk in individuals with chronic SCI.

Distinct components of cardiovascular health are linked with age-related differences in cognitive abilities

Cardiovascular ageing contributes to cognitive impairment. However, the unique and synergistic contributions of multiple cardiovascular factors to cognitive function remain unclear because they are often condensed into a single composite score or examined in isolation. We hypothesized that vascular risk factors, electrocardiographic features and blood pressure indices reveal multiple latent vascular factors, with independent contributions to cognition. In a population-based deep-phenotyping study (n = 708, age 18-88), path analysis revealed three latent vascular factors dissociating the autonomic nervous system response from two components of blood pressure. These three factors made unique and additive contributions to the variability in crystallized and fluid intelligence. The discrepancy in fluid relative to crystallized intelligence, indicative of cognitive decline, was associated with a latent vascular factor predominantly expressing pulse pressure. This suggests that higher pulse pressure is associated with cognitive decline from expected performance. The effect was stronger in older adults. Controlling pulse pressure may help to preserve cognition, particularly in older adults. Our findings highlight the need to better understand the multifactorial nature of vascular aging.

The effects of age on resting-state BOLD signal variability is explained by cardiovascular and cerebrovascular factors

Accurate identification of brain function is necessary to understand neurocognitive aging, and thereby promote health and well-being. Many studies of neurocognitive aging have investigated brain function with the blood-oxygen level-dependent (BOLD) signal measured by functional magnetic resonance imaging. However, the BOLD signal is a composite of neural and vascular signals, which are differentially affected by aging. It is, therefore, essential to distinguish the age effects on vascular versus neural function. The BOLD signal variability at rest (known as resting state fluctuation amplitude, RSFA), is a safe, scalable, and robust means to calibrate vascular responsivity, as an alternative to breath-holding and hypercapnia. However, the use of RSFA for normalization of BOLD imaging assumes that age differences in RSFA reflecting only vascular factors, rather than age-related differences in neural function (activity) or neuronal loss (atrophy). Previous studies indicate that two vascular factors, cardiovascular health (CVH) and cerebrovascular function, are insufficient when used alone to fully explain age-related differences in RSFA. It remains possible that their joint consideration is required to fully capture age differences in RSFA. We tested the hypothesis that RSFA no longer varies with age after adjusting for a combination of cardiovascular and cerebrovascular measures. We also tested the hypothesis that RSFA variation with age is not associated with atrophy. We used data from the population-based, lifespan Cam-CAN cohort. After controlling for cardiovascular and cerebrovascular estimates alone, the residual variance in RSFA across individuals was significantly associated with age. However, when controlling for both cardiovascular and cerebrovascular estimates, the variance in RSFA was no longer associated with age. Grey matter volumes did not explain age differences in RSFA, after controlling for CVH. The results were consistent between voxel-level analysis and independent component analysis. Our findings indicate that cardiovascular and cerebrovascular signals are together sufficient predictors of age differences in RSFA. We suggest that RSFA can be used to separate vascular from neuronal factors, to characterize neurocognitive aging. We discuss the implications and make recommendations for the use of RSFA in the research of aging.

Definition and early diagnosis of metabolic syndrome in children

With this review, we aim to focus the attention on some established as well as new concepts for the metabolic syndrome (MetS) in children and adolescents spanning from definition to recommendations for the diagnostic approach. Even though there is no international commonly used definition of the metabolic syndrome in children and adolescents, all definitions include obesity as precondition for the development of MetS even in children. Obesity is one of the major cardiometabolic risk factors and it is strongly linked to other metabolic diseases like hyperlipidemia, hyperinsulinemia as well as hypertension. The metabolic syndrome is commonly known as a constellation of the mentioned morbidities. Pediatricians and researchers agree that early diagnosis and early interventions of the MetS are important to improve the prevention of cardiovascular disease and type 2 diabetes in adulthood. However, this requires appropriate screening tools for children and adolescents at risk for the MetS and its comorbidities. Due to controversies regarding the definition of MetS and the lack of consensus thresholds for the single components in children and adolescents, there is no internationally accepted diagnostic pathway for MetS available. However, several consensus statements and national guidelines for the assessment of obesity and its comorbidities in children and adolescents are available. Obesity seems to be the driving factor for the development of the other risk factors of MetS. In order to avoid conflicts concerning the definition of overweight and obesity, we recommend using the WHO definition of overweight (one standard deviation body mass index for age and sex and obesity; two standard deviations body mass index for age and sex) in children and adolescents.

Metabolic syndrome in a sample of Egyptian adolescent girls and its association with apolipoprotein E

AIM

Obesity and its metabolic complications are increasing in childhood and extend to adulthood. The aims of this study were to assess the prevalence of metabolic syndrome (MS) in a sample of Egyptian adolescent girls and investigate its association with apolipoprotein E.

METHODS

A cross-sectional study design was used, including 200 Egyptian adolescent girls aged between 12 and 18 years. They were subjected to blood pressure (BP) measurement, anthropometric measurements (weight, height and waist circumference (WC)), laboratory investigations (fasting glucose and lipid profile) and molecular analysis (Apo E).

RESULTS

Overweight/obese girls were suffering significantly, more than normal-weight girls, from hypertension (66.7 vs. 40.8%), diabetes diagnosed by elevated fasting blood glucose (46.7 vs. 31.2%) and low high-density lipoprotein (HDL) (64 vs. 59.2%). Girls with MS had significantly higher values of body mass index Z-score, WC, BP, cholesterol and triglycerides and significantly lower HDL. Allele E3 (59.1 vs. 55.1%) was more frequent among girls with MS, while allele E4 (41 vs. 36.4) was more frequent among girls without MS. MS was the most prominent among girls with the E3/E4 genotype (35.7%), who had the highest frequency of elevated cholesterol, triglycerides, low-density lipoprotein and blood glucose, while girls with the E2/E4 genotype, which was rare among both groups, had the highest frequency of elevated BP (68.8%) and low HDL (71.4%).

CONCLUSION

MS was significantly more prominent among overweight/obese adolescent girls with the E3/E4 genotype, who had the highest frequency of disturbed lipid profile and blood glucose.

Cardiometabolic Risk Variables in Preadolescent Children: A Factor Analysis

BACKGROUND

Atherosclerosis begins during preadolescence and is occurring at an accelerated rate. This acceleration has been linked to poor lifestyle behaviors and subsequent cardiometabolic complications. Although the clustering of cardiometabolic risk factors has been recognized for over 2 decades, previous studies in children have predominantly examined the relationships between atherosclerosis and individual cardiometabolic risk factors or have grouped together preadolescent and adolescent children. Further, no known studies have included glycated hemoglobin or central hemodynamic measures such as central systolic blood pressure and augmentation index.

METHODS AND RESULTS

Principal component analysis was performed on a cross-sectional sample of 392 children (aged 9.5 years, 50% girls) from 3 representative sample sites across New Zealand. Four factors explained 60% of the variance in the measured variables. In order of variance explained, the factors were: blood pressure (central systolic blood pressure and peripheral systolic and diastolic blood pressure), adiposity (waist circumference, body mass index, and glycated hemoglobin), lipids (total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol), and vascular (augmentation index, heart rate, and fasting blood glucose).

CONCLUSIONS

In accordance with previous findings in adults and adolescents, one common factor is unlikely to define cardiometabolic health in preadolescent children. Each of the factors, except vascular, which was predominantly explained by augmentation index, are in agreement with previous findings in adolescents. An additional novel finding was that glycated hemoglobin and fasting blood glucose loaded onto different factors, supporting previous work suggesting that fasting blood glucose indicates short-term glycemic control, whereas glycated hemoglobin reflects chronic glycemic control.

CLINICAL TRIAL REGISTRATION

URL: www.anzctr.org.au/. ID: ACTRN12614000433606.

A systematic review of childhood obesity in the Middle East and North Africa (MENA) region: Prevalence and risk factors meta-analysis

Obesity rates are rising globally, but there is evidence that young people in the Middle East and North Africa (MENA) region are at particularly high risk. We systematically searched the literature to map the MENA region for prevalence of childhood overweight and obesity, and examine the underlying risk factors and adverse effects associated with obesity in this region. Inclusion criteria were: English-language, non-basic-science focused articles that used any of the standard obesity definitions and were conducted in the MENA countries within the last five years. We searched PubMed using combinations of key terms ((childhood) OR adolescence) AND obesity) AND (MENA or each country) AND ("last five years" [PDat]). Studies demonstrated an increasing prevalence of obesity among many countries in the MENA region, especially in the Gulf area. Notably, in Kuwait, prevalence rates of overweight and obesity were 25.6% and 34.8% among young males and 20.8% and 20.5% among females. A meta-analysis revealed that physical inactivity, increased screen time, and higher social status were risk factors for childhood obesity. Childhood and adolescent obesity is a major challenge facing countries of the MENA region. Further research is needed to fully investigate the role of nutrition and other specific risk factors and evaluate various interventions to manage this pervasive and growing health problem.

A systematic review of childhood obesity in the Middle East and North Africa (MENA) region: Health impact and management

Childhood obesity has serious consequences both immediately and in adulthood. The rates of obesity in children and adolescents are rising rapidly in the Middle East and North Africa (MENA) region. We systematically searched the literature to explore adverse effects associated with childhood obesity in this region and the management efforts for dealing with it. Inclusion criteria were: English-language, non-basic-science focused articles that used any of the standard obesity definitions and were conducted in the MENA countries within the last five years. We searched PubMed using combinations of key terms ((childhood) OR adolescence) AND obesity) AND (MENA or each country) AND ("last five years" [PDat]). Studies that examined adverse effects of childhood obesity gave fairly consistent results, revealing associations with higher blood pressure, pre-diabetes, metabolic abnormalities, and cardiovascular risk. Little or no overall effect on rates of childhood obesity has yet been demonstrated by interventions used to manage the problem. Obesity has a considerable impact on the health of children and adolescents, and the countries of the MENA region should endorse strategies and programs to prevent and manage this problem in an effective way.

Clinical characteristics in Taiwanese women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common hormonal endocrine disorders in women of reproductive age. It consists of a heterogeneous collection of signs and symptoms that together form a disorder spectrum. The diagnosis of PCOS is principally based on clinical and physical findings. The extent of metabolic abnormalities in women with PCOS varies with phenotype, body weight, age, and ethnicity. For general population, the prevalence of hyperandrogenism and oligomenorrhea decreases with age, while complications such as insulin resistance and other metabolic disturbances increase with age. Obese women with PCOS have a higher risk of developing oligomenorrhea, amenorrhea, hyperandrogenemia, insulin resistance, and lower luteinizing hormone (LH) to follicle stimulation hormone (FSH) ratios than non-obese women with PCOS. The LH to FSH ratio is a valuable diagnostic tool in evaluating Taiwanese women with PCOS, especially in the diagnosis of oligomenorrhea. Overweight/obesity is the major determinant of cardiovascular and metabolic disturbances in women of reproductive age.

Pathophysiological domains underlying the metabolic syndrome: an alternative factor analytic strategy

PURPOSE

Factor analysis (FA) has become part and parcel in metabolic syndrome (MBS) research. Both exploration- and confirmation-driven factor analyzes are rampant. However, factor analytic results on MBS differ widely. A situation that is at least in part attributable to misapplication of FA. Here, our purpose was (i) to review factor analytic efforts in the study of MBS with emphasis on misusage of the FA model and (ii) to propose an alternative factor analytic strategy.

METHODS

The proposed factor analytic strategy consists of four steps and confronts weaknesses in application of the FA model. At its heart lies the explicit separation of dimensionality and pattern selection and the direct evaluation of competing inequality-constrained loading patterns. A high-profile MBS data set with anthropometric measurements on overweight children and adolescents is reanalyzed using this strategy.

RESULTS

The reanalysis implied a more parsimonious constellation of pathophysiological domains underlying phenotypic expressions of MBS than the original analysis (and many other analyses). The results emphasize correlated factors of impaired glucose metabolism and impaired lipid metabolism.

CONCLUSIONS

Pathophysiological domains underlying phenotypic expressions of MBS included in the analysis are driven by multiple interrelated metabolic impairments. These findings indirectly point to the possible existence of a multifactorial etiology.

Remodelling of biological parameters during human ageing: evidence for complex regulation in longevity and in type 2 diabetes

Factor structure analyses have revealed the presence of specific biological system markers in healthy humans and diseases. However, this type of approach in very old persons and in type 2 diabetes (T2DM) is lacking. A total sample of 2,137 Italians consisted of two groups: 1,604 healthy and 533 with T2DM. Age (years) was categorized as adults (≤65), old (66-85), oldest old (>85-98) and centenarians (≥99). Specific biomarkers of routine haematological and biochemical testing were tested across each age group. Exploratory factorial analysis (EFA) by principal component method with Varimax rotation was used to identify factors including related variables. Structural equation modelling (SEM) was applied to confirm factor solutions for each age group. EFA and SEM identified specific factor structures according to age in both groups. An age-associated reduction of factor structure was observed from adults to oldest old in the healthy group (explained variance 60.4% vs 50.3%) and from adults to old in the T2DM group (explained variance 57.4% vs 44.2%). Centenarians showed three-factor structure similar to those of adults (explained variance 58.4%). The inflammatory component became the major factor in old group and was the first one in T2DM. SEM analysis in healthy subjects suggested that the glucose levels had an important role in the oldest old. Factorial structure change during healthy ageing was associated with a decrease in complexity but showed an increase in variability and inflammation. Structural relationship changes observed in healthy subjects appeared earlier in diabetic patients and later in centenarians.