Cardiometabolic disorder reduces survival prospects more than suboptimal body mass index irrespective of age or gender: a longitudinal study of 377,929 adults in Taiwan

Chih-Cheng Hsu,Yi-Fen Tsai,Mark L Wahlqvist,I-Shou Chang,Yu-Hung Chang,Chao A Hsiung,I-Chien Wu,Ting-Ting Liu,Chwen Keng Tsao

doi:10.1186/s12889-018-5038-0

Abstract

BackgroundThe effect of cardio-metabolic profile on the relationship of body mass index (BMI) with mortality is unclear. The aim of this study was to explore association between BMI and mortality at all ages, taking account of cardio-metabolic disorders.MethodsWe followed 377,929 individuals (≥ 20 years), who registered for health checkups in 1996–2007, until 2008 and found 9490 deaths. From multivariable Cox proportional hazards models we estimated mortality hazard ratios (HR) for those in high blood pressure, hyperglycemia, high waist circumference, dyslipidemia, and different BMIs categories (the underweight [< 18.5 kg/m2], low normal weight [18.5–21.9 kg/m2], normal weight [22–23.9 kg/m2, the referent], overweight [24–26.9 kg/m2], obese1 [27–29.9 kg/m2], and obese2 [≥ 30 kg/m2]). Population attributable risk (PAR) provided estimates of the population mortality burden attributable to high blood pressure, hyperglycemia, high waist circumference, dyslipidemia, and deviant BMIs.ResultsHigher blood pressure, hyperglycemia, high waist circumference, and dyslipidemia were significantly predictive of higher mortality for nearly all ages. Compared with the referent BMI, underweight (HR = 1.69, 95% confidence interval = 1.51–1.90) and low normal weight (HR = 1.19, 1.11–1.28) were significant mortality risks, while overweight (HR = 0.82, 0.76–0.89) and obese1 (HR = 0.88, 0.79–0.97) were protective against premature death. The mortality impact of obesity was largely attributable to cardio-metabolic profile and attenuated by age. The population mortality burden with high blood pressure (PAR = 7.29%), hyperglycemia (PAR = 5.15%), high waist circumference (PAR = 4.24%), and dyslipidemia (PAR = 5.66%) was similar to that in the underweight (PAR = 5.50%) or low normal weight (PAR = 6.04%) groups. Findings for non-smokers and by gender were similar.ConclusionsThe effect of BMI on mortality varies with age and is affected by cardio-metabolic status. Compared to any deviant BMI, abnormal cardio-metabolic status has a similar or even greater health impact at both the individual and population levels.

Highlights

The effect of cardio-metabolic profile on the relationship of body mass index (BMI) with mortality is unclear
For those younger than 50, overweight and obesity are associated with higher death rates; for people older than 50, those in the overweight category have the lowest mortality rate and those who are underweight have the highest
This indicates that the high mortality in underweight groups who have metabolic syndrome (MetS) is predominantly related to Cardio-metabolic factors (CMF)

Summary

Introduction

The effect of cardio-metabolic profile on the relationship of body mass index (BMI) with mortality is unclear. There is a general understanding that the body mass index (BMI) in itself is a major determinant of mortality [1], qualified by fat distribution for diseasespecific outcomes [2]. This may not always have been so [3]; but evidence from large-scale cohorts in both Western and Asian countries generally indicate that a BMI of 22–25 kg/m2 may be optimal for prevention of premature death [1, 4,5,6,7,8,9]. In an era when the prevalence of MetS has sharply increased [21], the predictive power of BMI for mortality relative to that of cardio-metabolic risk factors, hypertension and hyperglycemia, is required

Objectives

Methods

Results

Discussion

Conclusion