Population Attributable Fraction of Smoking and Metabolic Syndrome on Cardiovascular Disease Mortality in Japan: a 15-Year Follow Up of NIPPON DATA90

Naoyuki Takashima,Yoshitaka Murakami,Nagako Okuda,Akira Fujiyoshi,Akira Okayama,Aya Kadota,Tomonori Okamura,Takehito Hayakawa,Katsuyuki Miura,Hirotsugu Ueshima,Shin-Ya Nagasawa,Yoshikuni Kita,Atsushi Hozawa,Takashi Kadowaki,Yasuyuki Nakamura

doi:10.1186/1471-2458-10-306

Abstract

BackgroundSmoking and metabolic syndrome are known to be related to cardiovascular diseases (CVD) risk. In Asian countries, prevalence of obesity has increased and smoking rate in men is still high. We investigated the attribution of the combination of smoking and metabolic syndrome (or obesity) to excess CVD deaths in Japan.MethodsA cohort of nationwide representative Japanese samples, a total of 6650 men and women aged 30-70 at baseline without history of CVD was followed for 15 years. Multivariate-adjusted hazard ratio for CVD death according to the combination of smoking status and metabolic syndrome (or obesity) was calculated using Cox proportional hazard model. Population attributable fraction (PAF) of CVD deaths was calculated using the hazard ratios.ResultsDuring the follow-up period, 87 men and 61 women died due to CVD. The PAF component of CVD deaths in non-obese smokers was 36.8% in men and 11.3% in women, which were higher than those in obese smokers (9.1% in men and 5.2% in women). The PAF component of CVD deaths in smokers without metabolic syndrome was 40.9% in men and 11.9% in women, which were also higher than those in smokers with metabolic syndrome (7.1% in men and 3.9% in women).ConclusionOur results indicated that a large proportion of excess CVD deaths was observed in smokers without metabolic syndrome or obesity, especially in men. These findings suggest that intervention targeting on smokers, irrespective of the presence of metabolic syndrome, is still important for the prevention of CVD in Asian countries.

Highlights

Smoking and metabolic syndrome are known to be related to cardiovascular diseases (CVD) risk
Obesity and clustering of its related factors, called as metabolic syndrome, have been widely reported as important risk factors for cardiovascular diseases (CVD) [1,2,3,4,5,6], and, in Asian countries including Japan, obesity has emerged as a new health problem [5]
The hazard ratios (HR) of CVD deaths in smokers without metabolic syndrome were higher than non-smokers without metabolic syndrome, and it was similar to the HR in smokers with metabolic syndrome (3.47 vs. 3.19)

Summary

Introduction

Smoking and metabolic syndrome are known to be related to cardiovascular diseases (CVD) risk. In Asian countries, prevalence of obesity has increased and smoking rate in men is still high. Obesity and clustering of its related factors, called as metabolic syndrome, have been widely reported as important risk factors for cardiovascular diseases (CVD) [1,2,3,4,5,6], and, in Asian countries including Japan, obesity has emerged as a new health problem [5]. Cigarette smoking is an established risk factor for CVD [8,9,10,11,12] and one of the biggest health problems in Asian countries including Japan [9,12,13]. In Asian countries, smoking rate in men is still high at 40 to 50% [14]. Smoking has largely contributed to increase CVD events in Asia, and it was reported that up to 30% of cardiovascular deaths was attributed by smoking in Asia Pacific region [16]

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