Population attributable fraction of smoking and metabolic syndrome on cardiovascular disease mortality in Japan: a 15-year follow up of NIPPON DATA90.
BACKGROUND
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. We investigated the attribution of the combination of smoking and metabolic syndrome (or obesity) to excess CVD deaths in Japan.


METHODS
A 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.


RESULTS
During 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).


CONCLUSIONS
Our 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.
Takashima
Naoyuki
N
Department of Health Science, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga 520-2192, Japan. takasima@belle.shiga-med.ac.jp
Miura
Katsuyuki
K
Hozawa
Atsushi
A
Kadota
Aya
A
Okamura
Tomonori
T
Nakamura
Yasuyuki
Y
Hayakawa
Takehito
T
Okuda
Nagako
N
Fujiyoshi
Akira
A
Nagasawa
Shin-Ya
SY
Kadowaki
Takashi
T
Murakami
Yoshitaka
Y
Kita
Yoshikuni
Y
Okayama
Akira
A
Ueshima
Hirotsugu
H
D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000209:etiology / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications*; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects*