Atherosclerosis 233 (2014) 27e29

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Overall diet quality and risk of stroke: A prospective cohort study in women Susanna C. Larsson*, Agneta Åkesson, Alicja Wolk Division of Nutritional Epidemiology, National Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-17177 Stockholm, Sweden

a r t i c l e i n f o

a b s t r a c t

Article history: Received 22 July 2013 Received in revised form 12 October 2013 Accepted 25 November 2013 Available online 18 December 2013

Data on overall diet quality in relation to stroke risk are sparse. We examined the association between consumption of a diversity of recommended and non-recommended foods and risk of stroke. The study population comprised 33 911 Swedish women who had completed a questionnaire in 1997 and were free from cardiovascular disease and cancer. We calculated a Recommended Food Score (RFS) based on 25 healthy food items and a Non-Recommended Food Score (NRFS), consisting of 21 food items considered less healthy. Stroke cases were identified through linkage to Swedish registers. During 11 years of followup, we ascertained 1687 stroke cases. The multivariable relative risks of stroke for the highest versus lowest quintile were 0.80 (95% CI, 0.67e0.95) for RFS and 1.22 (95% CI, 1.02e1.46) for NRFS. In conclusion, these findings suggest that a diet including a variety of healthy foods and few less healthy foods may reduce stroke risk. Ó 2013 Elsevier Ireland Ltd. All rights reserved.

Keywords: Diet Foods Prospective studies Stroke

1. Introduction Stroke is a major cause of morbidity and mortality in Western countries. It has been estimated that 80% of stroke events can be prevented (secondary prevention) through modifiable risk factors, including diet [1]. Most studies on diet and stroke have focused on the role of specific nutrients, foods, or food groups rather than the whole diet. Because foods are consumed in combination, the combined effect of diet on stroke risk may be assessed by considering the entire eating pattern, which accounts for interactions between foods containing different nutrients. The aim of this study was to investigate the association between a Recommended Food Score (RFS), derived from food-based recommendations [2], and stroke risk in the Swedish Mammography Cohort (SMC). We also assessed whether consumption of a diversity of non-recommended foods (Non-Recommended Food Score; NRFS), i.e., foods considered less healthy, was associated with an increased risk of stroke. 2. Methods 2.1. Study population The SMC provided data for the present analyses. Detailed information about this cohort has been published previously [3]. The * Corresponding author. Tel.: þ46 8 52486059; fax: þ46 8 304571. E-mail address: [email protected] (S.C. Larsson). 0021-9150/$ e see front matter Ó 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.atherosclerosis.2013.11.072

study population for the present analysis included 33 911 participants of the SMC study who had completed a questionnaire in 1997 and were free from cardiovascular disease and cancer. The study was approved by the Regional Ethical Review Board at Karolinska Institutet in Stockholm, Sweden. 2.2. Data collection In 1997, all participants had completed a questionnaire that sought information on education, weight, height, smoking, physical activity, aspirin use, history of hypertension, family history of myocardial infarction, alcohol consumption, and diet. Pack-years of smoking history were calculated as the number of cigarette packs smoked daily multiplied by the number of years of smoking. Calculation of total physical activity has been described previously [3]. 2.3. Dietary assessment Diet was assessed using a 96-item food-frequency questionnaire (FFQ). Participants were asked to indicate how often, on average, they had consumed various foods over the past year, with 8 predefined frequency categories ranging from never to 3 times/day. For commonly consumed foods, such as dairy products and bread, participants were asked to indicate the exact number of servings per day or week. A diet with a variety of healthy foods was defined according to a RFS, which is a way to define the overall diet quality by separating ‘healthy’ from ‘less healthy’ foods based on current

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S.C. Larsson et al. / Atherosclerosis 233 (2014) 27e29

Table 1 Relative risk of stroke by quintiles of Recommended and Non-recommended Food Scores among 33,911 Swedish women. Score/no. of foods (mean)

RFS 1e16 (14) 17e18 (18) 19e20 (20) 21e22 (22) 23e25 (23) P for trendc NRFS 1e10 (9) 11e12 (12) 13e14 (14) 15e16 (15) 17e21 (18) P for trendc

Total stroke

Cerebral infarction

Hemorrhagic strokea

No. of cases

Person-years

Age-adjusted RR (95% CI)

Multivariable RR (95% CI)b

No. of cases

Multivariable RR (95% CI)b

No. of cases

Multivariable RR (95% CI)b

463 251 325 378 270

65 42 66 91 85

825 200 586 803 944

1.00 1.08 1.00 0.93 0.80 0.02

(reference) (0.92e1.26) (0.87e1.15) (0.81e1.07) (0.68e0.93)

1.00 1.07 0.98 0.92 0.80 0.03

(reference) (0.91e1.26) (0.84e1.15) (0.79e1.08) (0.67e0.95)

337 205 237 277 204

1.00 1.20 1.00 0.95 0.86 0.15

(reference) (1.00e1.45) (0.83e1.20) (0.79e1.14) (0.70e1.05)

60 34 56 64 42

1.00 0.98 1.05 0.89 0.66 0.17

(reference) (0.63e1.51) (0.71e1.56) (0.60e1.33) (0.42e1.04)

374 255 365 374 319

55 48 73 90 84

632 928 547 187 064

1.00 0.92 1.02 0.96 1.05 0.56

(reference) (0.79e1.08) (0.88e1.18) (0.83e1.10) (0.90e1.22)

1.00 0.97 1.10 1.07 1.22 0.02

(reference) (0.82e1.14) (0.94e1.28) (0.91e1.26) (1.02e1.46)

276 194 275 280 235

1.00 1.01 1.13 1.11 1.27 0.02

(reference) (0.83e1.21) (0.95e1.36) (0.92e1.34) (1.03e1.56)

47 34 50 63 62

1.00 0.89 0.94 1.06 1.25 0.26

(reference) (0.35e1.13) (0.48e1.37) (0.75e1.84) (0.80e2.94)

RFS ¼ recommended food score (variety of healthy foods); NRFS ¼ non-recommended food score (variety of foods considered unhealthy). a Intracerebral hemorrhage and subarachnoid hemorrhage. b Multivariable relative risks were estimated using Cox proportional hazards regression model (with age as time scale) and were adjusted for education (less than high school, high school, or university), smoking (never; past

Overall diet quality and risk of stroke: a prospective cohort study in women.

Data on overall diet quality in relation to stroke risk are sparse. We examined the association between consumption of a diversity of recommended and ...
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