The Relationship between Metabolically Healthy Obesity and the Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis

Abstract

Cardiovascular disease (CVD) risk in individuals with metabolically healthy obesity (MHO) is unclear. We searched databases from inception to May 2019. Data were pooled using a random effects model. Newcastle-Ottawa Scale assessment was performed. Primary and secondary outcomes were CVD risk and all-cause mortality. Forty-three studies involving 4,822,205 cases were included. The median percentage of females, age and duration of follow-up was 52%, 49.9 years and 10.6 years, respectively. The mean Newcastle-Ottawa Scale score of the articles was 7.9 ± 1.0. Compared to individuals with a metabolically healthy normal weight, individuals with MHO had higher adjusted risk of CVD and all-cause mortality. We identified a significant linear dose-response relationship between body mass index (BMI) and CVD risk among metabolically healthy individuals (p < 0.001); every unit increase in BMI increased the CVD risk. Multivariate meta-regression analysis showed that an increased proportion of women and age resulted in the risk of CVD affected by MHO reduction (p = 0.014, p = 0.030, respectively). Age and sex explained the observed heterogeneity and reported the adjusted R2. MHO resulted in a significantly increased risk for CVD; therefore, long-term weight loss should be encouraged.

The Association between Metabolically Healthy Obesity, Cardiovascular Disease, and All-Cause Mortality Risk in Asia: A Systematic Review and Meta-Analysis

“…Similar to a previous study [7], we found that MHO increased the risk of CVD and all-cause mortality compared with MHNW in the Asian population. This result was more striking for CVD than for all-cause mortality.…”

“…Thus, increased CVD risk is associated with lower BMI in Asians than in Caucasians [29]. Although a previous meta-analysis revealed sex and age to be significant effect modifiers [7], we found no significant effect, and further studies may be warranted. Sex-related differences in CVD risk could be explained by variations in visceral adipose tissue accumulation, deposition, and distribution which have been associated with insulin resistance and metabolic risks [30,31].…”

“…Several cohort studies have discussed the relationship between MHO and CVD risk and all-cause mortality. While recent systematic reviews have confirmed the relationship between MHO and increased CVD risk and all-cause mortality compared with "metabolically healthy normal weight (MHNW)" [7,8], most of these studies included only Caucasian populations. Furthermore, in several Korean studies that compared MHO individuals with "metabolically healthy non-obese (MHNO)", individuals are classified as obese or non-obese, and data on overweight and underweight individuals were excluded from these meta-analyses [5,9].…”

“…Furthermore, in several Korean studies that compared MHO individuals with "metabolically healthy non-obese (MHNO)", individuals are classified as obese or non-obese, and data on overweight and underweight individuals were excluded from these meta-analyses [5,9]. Multivariate meta-analysis in previous research disclosed that the increasing age and proportion of women in MHO group led to the decline of CVD risk, which indicated that age and gender may be important effect modifiers [7]. Therefore, this research tried to survey if a similar effect can be found among the Asian group.…”

The association between metabolically healthy obesity and risk of cancer: A systematic review and meta‐analysis of prospective cohort studies

“…13 Previous meta-analyses on MHO primarily focused on the risk of cardiometabolic disease. [14][15][16][17] To date, no systematic review or metaanalysis reported the impact of MHO on the risk of cancer. One cohort study demonstrated that individuals with MHO were at increased risk of prostate cancer compared with individuals with metabolically healthy non-obesity (MHNO).…”