Metabolically Obese Individuals of Normal Weight Have a High Risk of 25-Hydroxyvitamin D Deficiency

Differences in the levels of inflammatory markers between metabolically healthy obese and other obesity phenotypes in adults: A systematic review and meta-analysis

AIMS

The aim of this study was to systematically review and analyze differences in the levels of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) comparing metabolically healthy but obese (MHO) with metabolically healthy non-obese (MHNO), metabolically unhealthy non-obese (MUNO), and metabolically unhealthy obese (MUO) subjects.

DATA SYNTHESIS

We searched PubMed, Embase, Web of Science, and Scopus for studies that matched the relevant search terms. Differences in inflammatory marker levels between MHO and the other three phenotypes were pooled as standardized mean differences (SMD) or differences of medians (DM) using a random-effects model. We included 91 studies reporting data on 435,007 individuals. The CRP levels were higher in MHO than in MHNO subjects (SMD = 0.63, 95% CI: 0.49, 0.76; DM = 0.83 mg/L, 95% CI: 0.56, 1.11). The CRP levels were higher in MHO than in MUNO subjects (SMD = 0.16, 95% CI: 0.05, 0.28; DM = 0.39 mg/L, 95% CI: 0.09, 0.69). The CRP levels were lower in MHO than in MUO individuals (SMD = -0.43, 95% CI: -0.54, -0.31; DM = -0.82 mg/L, 95% CI: -1.16, -0.48). The IL-6 levels in MHO were higher than in MHNO while lower than in MUO subjects. The TNF-α levels in MHO were higher than in MHNO individuals.

CONCLUSIONS

This review provides evidence that CRP levels in MHO are higher than in MHNO and MUNO subjects but lower than in MUO individuals. Additionally, IL-6 levels in MHO are higher than in MHNO but lower than in MUO subjects, and TNF-α levels in MHO are higher than in MHNO individuals.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO number: CRD42021234948.

Vitamin D Determinants, Status, and Antioxidant/Anti-inflammatory-Related Effects in Cardiovascular Risk and Disease: Not the Last Word in the Controversy

Beyond its key role in calcium homeostasis, vitamin D has been found to significantly affect the cardiovascular (CV) system. In fact, low vitamin D levels have been associated with increased CV risk, as well as increased CV morbidity and mortality. The majority of effects of this molecule are related directly or indirectly to its antioxidative and anti-inflammatory properties. Generally, vitamin D insufficiency is considered for 25-hydroxyvitamin D (25(OH)D) levels between 21-29 ng/mL (corresponding to 52.5-72.5 nmol/L), deficiency as 25(OH)D levels less than 20 ng/mL (<50 nmol/L), and extreme deficiency as 25(OH)D less than 10 ng/mL (<25 nmol/L). However, the definition of an optimal vitamin D status, as defined by 25(OH)D, remains controversial for many extra-bone conditions, including CV disease. In this review, confounding factors affecting the 25(OH)D measurement and status will be discussed. In particular, available evidence on the mechanism and role of vitamin D in relation to CV risk and disease through its antioxidant effect will be reported, also facing the aspect regarding the debate on the minimum blood 25(OH)D level required to ensure optimal CV health.

Vitamin D is directly associated with favorable glycemic, lipid, and inflammatory profiles in individuals with at least one component of metabolic syndrome irrespective of total adiposity: Pró-Saúde Study, Brazil

Vitamin D insufficiency has been suggested as a risk factor for several metabolic disorders. The objective of the study was to investigate the association between serum 25 hydroxyvitamin D [25(OH)D] and metabolic health markers of Brazilian individuals with normal-weight, overweight or obesity. We hypothesized that serum 25(OH)D would be inversely associated with glycemic, lipid and inflammatory markers indicative of metabolic abnormality. Data of 511 individuals (33-79 years), recruited from a longitudinal investigation (Pró-Saúde Study), were analyzed cross-sectionally. Anthropometric, biochemical, body composition, socio-demographic and lifestyle data were collected. Based on body mass index (BMI; normal weight, overweight, obesity) and metabolic health (metabolically healthy (MH) and metabolically unhealthy (MU)) categories, the participants were classified into 6 phenotypes. Individuals having zero components of the metabolic syndrome were considered as "MH". MH obesity was frequent in 2.0% of the participants and 56.0% exhibited vitamin D insufficiency (<20 ng/mL). In the subgroups of the same BMI category, there were no significant differences in 25(OH)D concentrations between individuals classified as MH and MU. After adjustments (including %body fat and BMI), an inverse association was observed between 25(OH)D and visceral adipose tissue (B = -6.46, 95% confidence interval, CI: -12.87, -0.04), leptin (B = -0.09, 95% confidence interval, CI: -0.14, -0.03), insulin (B = -0.21, 95%CI: -0.34, -0.07), HOMA-IR (B = -0.06, 95%CI: -0.10, -0.02), triglycerides (B = -2.44, 95%CI: -3.66, -1.22), and TNF-α (B = -0.12, 95%CI: -0.24, -0.005) only in MU individuals. Our results indicate that the association of 25(OH)D concentrations with a favorable biochemical profile (glycemic, lipidic and inflammatory) seems to depend on the individual's overall metabolic health, suggesting more benefits from higher serum vitamin D in MU individuals, regardless of their adiposity.

Serum vitamin D levels in relation to abdominal obesity: A systematic review and dose-response meta-analysis of epidemiologic studies

Although several observational studies have investigated the relationship between vitamin D deficiency and risk of central obesity, the results were inconsistent. We performed a dose-response meta-analysis on epidemiologic studies that evaluated the association of vitamin D status and abdominal obesity in adults. A systematic search was carried out of all published articles, up to May 2020, in five electronic databases, including MEDLINE (Pubmed), EMBASE, Institute for Scientific Information (ISI) (Web of science), Scopus and Google scholar. Forty-one observational studies reported odds ratios (ORs) or relative risks (RRs) with 95% confidence intervals (CIs) for abdominal obesity in relation to serum vitamin D levels in adults were included in the analysis. Using a random effects model, the overall effect size was calculated. Combining 44 effect sizes from 36 cross-sectional studies with 257,699 participants revealed that the highest versus the lowest serum vitamin D level was significantly associated with a 23% decreased odds of abdominal obesity (OR: 0.77; 95% CI [0.71, 0.83]). This inverse association was significant in almost all subgroups based on different covariates. Dose-response analysis showed that each 25 nmol/L increase in serum vitamin D was related to 8% reduced risk of abdominal obesity (OR: 0.92; 95% CI [0.85, 0.99]). When we confined the analysis to 23 effect sizes from 17 studies with representative population (242,135 participants), the same results were obtained (OR: 0.79; 95% CI [0.71, 0.87]). Dose-response analysis indicated that each 25 nmol/L increase in blood vitamin D levels was linked to 10% decreased central adiposity risk in representative populations (OR: 0.90; 95% CI [0.82, 0.99]). This meta-analysis of epidemiologic studies revealed that serum vitamin D level was inversely associated with risk of abdominal obesity in adults, in a dose-response manner. The same findings were obtained in representative populations. Further prospective studies are required to examine the causal association between serum vitamin D levels and abdominal obesity.

Ethnic differences in metabolic cardiovascular risk among normal weight individuals: Implications for cardiovascular risk screening. The HELIUS study

BACKGROUND AND AIMS

Cardiovascular disease (CVD) risk factors may occur among a substantial proportion of normal weight individuals, particularly among some ethnic minorities. It is unknown how many of these individuals would be missed by commonly applied eligibility criteria for cardiovascular risk screening. Thus, we aim to determine cardiovascular risk and eligibility for cardiovascular risk screening among normal weight individuals of different ethnic backgrounds.

METHODS AND RESULTS

Using the HELIUS study (Amsterdam, The Netherlands), we determined cardiovascular risk among 6910 normal weight individuals of Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Moroccan and Turkish background. High cardiovascular risk was approximated by high metabolic risk based on blood pressure, HDL, triglycerides and fasting glucose. Eligibility criteria for screening were derived from Dutch CVD prevention guidelines and include age ≥ 50 y, family history of CVD, or current smoking. Ethnic group comparisons were made using logistic regression. Age-adjusted proportions of high metabolic risk ranged from 12.6% to 38.4% (men) and from 2.7% to 11.5% (women). This prevalence was higher among most ethnic minorities than the Dutch, especially among women. For most ethnic groups, 79.9%-86.7% of individuals with high metabolic risk were eligible for cardiovascular risk screening. Exceptions were Ghanaian women (58.8%), Moroccan men (70.9%) and Moroccan women (45.0%), although age-adjusted proportions did not differ between groups.

CONCLUSION

Even among normal weight individuals, high cardiovascular metabolic risk is more common among ethnic minorities than among the majority population. Regardless of ethnicity, most normal weight individuals with increased risk are eligible for cardiovascular risk screening.

Metabolically healthy obese and unhealthy normal weight in Iranian adult population: Prevalence and the associated factors

AIMS

The objective of this study was to determine the prevalence and the associated factors of metabolically unhealthy in normal-weight and metabolically healthy in obese.

METHODS

We analyzed the data of a representative sample of 986 participants recruited among adult population of north of Iran. Data were collected regarding demographic characteristics, lifestyle, body mass index, abdominal obesity measures, blood pressure, and lipid profiles. The participants were classified as metabolically healthy obese (MHO) and metabolically unhealthy normal-weight (MUNW). Metabolically unhealthy was defined as the presence of  ≥2 non-obese components of metabolic syndrome based on ATP III criteria.

RESULTS

The prevalence rate of MUNW and MHO accounted for 17.2% and 15.1% respectively. Mean age of participants with metabolically unhealthy was significantly greater than metabolically healthy in both normal weight and overweight/obese (P=0.001). The results of multiple logistic regression analysis showed in normal-weight individuals, a significant association of MUNW was found with age group of 50-59 years(OR=3.83, 95%CI: 1.71-8.57) and 60-70 years by OR=4.74(95%CI:1.79-12.54) as compared with age group of 20-29 years. It was also associated with current smoking. While metabolically healthy state in overweight/obese was inversely associated with age 50-59 years by OR=0.26 (95%CI:0.13-0.54) and age 60-70 years by OR=0.15 (95%CI:0.05- 0.39) and higher WC by OR=0.47 (95%CI:0.31-0.72) but positively associated with female-sex by OR=1.74 (95%CI:1.07-2.82).

CONCLUSION

Aging and smoking are significantly associated with metabolic abnormalities in normal-weight while aging, abdominal obesity negatively and female positively associated with metabolically healthy in obese.