Body Mass Index and Risk of Total and Type-Specific Stroke in Chinese Adults: Results from a Longitudinal Study in China

Abstract

Background

The prevalence rate of overweight and obese has been escalating over the past two decades in China. Even so, the association between obesity and stroke still remains unclear to some extent.

Aims

The aim of this study was to elucidate the association between body mass index and stroke in a large Chinese population cohort.

Methods

A cohort of 26 607 Chinese people, aged over 35 years, was investigated in 1987. Baseline information of body weight and height was used to calculate BMI (weight in kilograms divided by height in meters squared, kg/m²). Cox proportional hazards model was fitted to estimate hazard ratios of stroke adjusted for age, educational level, smoking and alcohol consumption.

Results

The 11-year follow-up revealed (241 149 person-years) a total of 1108 stroke events (614 ischemic, 451 hemorrhagic, and 44 undefined stroke). Body mass index ≥ 30·0 was an independent risk factor for stroke both in men and women. Compared with normal weight, hazard ratios for total stroke were 0·74 in men underweight (95% confidence interval: 0·53∼1·03), 1·63 overweight (95% confidence interval: 1·35∼1·96), and 2·20 with obesity (95% confidence interval: 1·47∼3·30); and with ischemic stroke, hazard ratios were 0·52 in those underweight (95% confidence interval: 0·30∼0·89), 208 overweight (95% confidence interval: 1·65∼2·62), and 3·80 with obesity (95% confidence interval: 2·47∼5·86). In women, the corresponding hazard ratios for total stroke were 0·79 underweight (95% confidence interval: 0·58∼1·07), 1·42 overweight (95% confidence interval: 1·16∼1·73), and 1·57 with obesity (95% confidence interval: 1·06∼2·31); and for those with ischemic stroke, 0·92 underweight (95% confidence interval: 0·59∼1·43), 1·90 overweight (95% confidence interval: 1·44∼2·50), and 2·42 with obesity (95% confidence interval: 1·50∼3·93). There appeared an evident dose-response relationship between body mass index and the risk of developing stroke, which still appeared, however, adjusted low for hypertension, diabetes, and heart disease. Decreased risk for stroke in the leanest group was confined to men only. No association was found between body mass index and hemorrhagic stroke in both genders.

Conclusions

Our data suggest that body mass index was an independent risk factor for total and ischemic stroke but not for hemorrhagic stroke in both genders. Association between body mass index and stroke was extremely mediated by hypertension, diabetes, and heart disease. Decreased risk for the leanest group was confined to men.

Keywords

body mass index (BMI)cohort study ischemic stroke obesity stroke stroke subtypes

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References

Wang

Shan

Wang

. Is China facing an obesity epidemic and the consequences? The trends in obesity and chronic disease in China. Int J Obes (Lond) 2007; 31:177–88.

Reynolds

. Prevalence of the metabolic syndrome and overweight among adults in China. Inter ASIA Collaborative Group. Lancet 2005; 365:1398–405.

Field

Coakley

Must

. Impact of overweight on the risk of developing common chronic diseases during a 10-year period. Arch Intern Med 2001; 161:1581–6.

Rimm

Stampfer

Giovannucci

. Body size and fat distribution as predictors of coronary heart disease among middle-aged and older US men. Am J Epidemiol 1995; 141:1117–27.

Willett

Manson

Stampfer

. Weight, weight change, and coronary heart disease in women. Risk within the ‘normal’ weight range. JAMA 1995; 273:461–5.

Ni Mhurchu

Rodgers

Pan

Woodward

. Asia Pacific Cohort Studies Collaboration. Body mass index and cardiovascular disease in the Asia-Pacific Region: An overview of 33 cohorts involving 310 000 participants. Int J Epidemiol 2004; 33:751–8.

Kurth

Gaziano

Berger

. Body mass index and the risk of stroke in men. Arch Intern Med 2002; 162:2557–62.

Benfante

Yano

Hwang

Curb

Kagan

Ross

. Elevated serum cholesterol is a risk factor for both coronary heart disease and thromboembolic stroke in Hawaiian Japanese men: Implications of shared risk. Stroke 1994; 25:814–20.

Stokes

3rd Kannel

Wolf

Cupples

D'Agostino

. The relative importance of selected risk factors for various manifestations of cardiovascular disease among men and women from 35 to 64 years old: 30 years of follow-up in the Framingham Study. Circulation 1987; 75(Suppl. V):V65–73.

10.

Njølstad

Arnesen

Lund-Larsen

. Body height, cardiovascular risk factors, and risk of stroke in middle-aged men and women: A 14-year follow-up of the Finmark Study. Circulation 1996; 94:2877–82.

11.

Singh

Lindsted

Fraser

. Body weight and mortality among adults who never smoked. Am J Epidemiol 1999; 150:1152–64.

12.

Fang

Zhang

Yang

. Subtype hypertension and risk of stroke in middle-aged and older Chinese: A 10-year follow-up study. Stroke 2006; 37:38–43.

13.

Fang

Kronmal

. Prevention of stroke in urban China: A community-based intervention trial. Stroke 1999; 30:495–501.

14.

Fang

Longstreth

Jr Li

. Longitudinal study of blood pressure and stroke in over 37,000 people in China. Cerebrovasc Dis 2001; 11:225–9.

15.

Oki

Nakamura

Okamura

. Body mass index and risk of stroke mortality among a random sample of Japanese adults: 19-year follow-up of NIPPON DATA80. Cerebrovasc Dis 2006; 22:409–15.

16.

Petitti

Sidney

Bernstein

Wolf

Quesenberry

Ziel

. Stroke in users of low-dose contraceptives. N Engl J Med 1996; 335:8–15.

17.

Rodriguez

D'Agostino

Abbott

. Risk of hospitalized stroke in men enrolled in the Honolulu Heart Program and the Framingham Study: A comparison of incidence and risk factor effects. Stroke 2002; 33:230–6.

18.

Song

Sung

Davey Smith

Ebrahim

. Body mass index and ischemic and hemorrhagic stroke: A prospective study in Korean men. Stroke 2004; 35:831–6.

19.

Rexrode

Hennekens

Willett

. A prospective study of body mass index, weight change, and risk of stroke in women. JAMA 1997; 277:1539–45.

20.

Jood

Jern

Wilhelmsen

Rosengren

. Body mass index in mid-life is associated with a first stroke in men. A prospective population study over 28 years. Stroke 2004; 35:2764–9.

21.

Kurth

Gaziano

Rexrode

. Prospective study of body mass index and risk of stroke in apparently healthy women. Circulation 2005; 111:1992–8.

22.

Wannamethee

Shaper

. Patterns of alcohol intake and risk of stroke in middle-aged British men. Stroke 1996; 27:1033–9.

23.

Hall

Brands

Hildebrandt

Mizelle

. Obesity-associated hypertension: Hyperinsulinemia and renal mechanisms. Hypertension 1992; 19(Suppl. I):I45–55.

24.

Egan

Stepniakowski

. Vascular alpha-adrenergic tone in obesity and salt-sensitive hypertension; in Laragh

Brenner

(eds): Hypertension: Pathophysiology, Diagnosis, and Management, 2nd edn. New York, Raven Press, 1995:2693–702.

25.

Mann

. The influence of obesity on health (second of two parts). N Engl J Med 1974; 291:226–32.

26.

Matsuzawa

Shimomura

Nakamura

Keno

Kotani

Tokunaga

. Pathophysiology and pathogenesis of visceral fat obesity. Obes Res 1995; 3(Suppl. 2):187S–94S.

27.

Horlick

. Dyslipidemia and metabolic factors in the genesis of heart attack and stroke. Health Rep 1994; 6:94–9.