P4410Normal weight central obesity and 10-year cardiovascular disease onset in apparently healthy males and females: the interacting effect of sex
Authors: Kouvari M , Panagiotakos D B , Yannakoulia M , Chrysohoou C , Georgousopoulou E , Tousoulis D , Pitsavos C 
Published: October 2019

Abstract

Background/Introduction
The notion that standard weight–height tables are the proper way to determine high-risk groups for obesity-related disorders has been largely challenged, yet scarce data exist from the standpoint of sex.

Purpose
To evaluate the effect of combined weight and waist-circumference (WC) status on 10-year first fatal/non fatal cardiovascular disease (CVD) event in apparently healthy males and females.

Methods
A prospective study (2001–2012) was conducted in Greece with n=1,514 males and n=1,528 females (aged >18 years old) free of CVD. Follow-up assessment of CVD event (2011–2012) was achieved in n=2,020 participants (317 cases). Normal weight (NW) status was defined as body mass index (BMI) from 18.5kg/m2 to 25kg/m2 while central obesity as WC≥102cm for males and ≥88cm for females. NW central obesity (NWO) was defined as BMI within the normal range and abnormal WC.

Results
The prevalence of NWO reached 10% (n=302) with female:male ratio being close to 4:1 (p<0.001). Within NW group ∼25% of participants presented increased WC. Ten-year CVD incidence in NWO subjects reached 14.1% which was twice as high as the respective rate for NW participants without central obesity (7.4%) and followed by the 15.4% and 24.1% in overweight/obese participants without or with central obesity, respectively (p<0.001). The female:male CVD event rate ratio was 0.37, 0.77, 0.42, 0.64 ranking from NW participants without central obesity to NWO and overweight/obese without or with central obesity (p<0.001). Cox regression analysis revealed that NWO status was independently associated with 10-year CVD event (Hazard Ratio (HR)=1.87, 95% Confidence Interval (95% CI) 1.04, 3.37, p=0.03) when compared with their NW counterparts with normal WC, after adjusting for sociodemographic, clinical, lifestyle and biochemical factors (i.e. insulin resistance and systemic inflammation). When NWO subjects were set as reference group and compared with their overweight/obese counterparts with or without central obesity, no significant trends were observed (all ps>0.05). A significant interaction between sex and the combined weight and central obesity status was observed (p for interaction<0.001). Stratified analysis revealed that the aforementioned associations were retained only in NWO females (HR=2.35, 95% CI 1.15, 4.79, p=0.01) when compared with their NW counterparts without central obesity; in males the association did not reach the level of significance. C-statistics [C-index (95% CI)] revealed that within the NW range, WC-adjusted model had a better discriminative ability in females [0.810 (0.778, 0.842)] compared with males [0.789 (0.763, 0.810)] while a BMI-adjusted model seemed to discriminate better the CVD event in males [0.801 (0.772, 0.831)] than in females [0.762 (0.731, 0.798)].

Conclusion
Studies addressing the complex interaction between fat and BMI as well as its effect on CVD are demanded, yet with the potential to highlight sex-specific remarks.

Acknowledgement/Funding
The ATTICA study is supported by research grants from the Hellenic Cardiology Society [HCS2002] and the Hellenic Atherosclerosis Society [HAS2003].