Pizza and risk of acute myocardial infarction

Article metrics

Abstract

Objectives: Pizza eating has been favourably related to the risk of cardiovascular disease, but the data are limited. To evaluate the potential role of pizza consumption on the risk of acute myocardial infarction (AMI), we considered data from an Italian study.

Design: We conducted a hospital-based case–control study on 507 cases of nonfatal AMI and 478 controls in Milan, Italy, between 1995 and 1999.

Results: The multivariate odds ratios were 0.78 for occasional, 0.62 for regular and 0.44 for frequent eaters. The estimates were similar across strata of age, sex, smoking and other major covariates.

Conclusions: Some of the ingredients of pizza have been shown to have a favourable influence on the risk of cardiovascular disease. However, there is no single explanation for the present findings. Pizza may in fact represent a general indicator of Italian diet, that has been shown to have potential cardiovascular benefits.

Introduction

Pizza has been favourably related to the risk of cardiovascular disease (CVD) and cancer, but the data are limited. In the Women's Health Study, a prospective study of almost 40 000 middle-age and older women and based on 719 CVD cases, an inverse association was found between pizza and CVD, the multivariate relative risk being 0.66 for ≥2 portions per week (Sesso et al, 2003). In a network of case–control studies from several Italian regions, pizza eating was inversely related to the risk of several digestive tract cancers (Gallus et al, 2003). Since pizza is one of the most widespread and best-known Italian foods, Italy represents the ideal environment to investigate potential relations between pizza eating and disease risk.

Methods

We considered the potential role of pizza consumption on the risk of acute myocardial infarction (AMI) in a case–control study conducted in Milan, Italy, between 1995 and 1999 (Tavani et al, 2001). Cases were 507 patients (378 men, 129 women, aged 25–79 y, median age 61 y) in hospital with a first episode of nonfatal AMI and controls were 478 patients (297 men, 181 women, aged 25–79 y, median age 59 y) admitted to the same hospitals for acute conditions unrelated to AMI risk factors (34% traumas, 30% nontraumatic orthopaedic disorders, 14% surgical conditions, 22% miscellaneous other diseases). Interviews were conducted in the hospital using a structured questionnaire, including information on socio-demographic factors, anthropometric variables, tobacco, alcohol, other lifestyle habits, medical history, physical activity and family history of AMI. The subject's usual diet before diagnosis (or hospital admission) was investigated using a validated 78-item food frequency questionnaire (Franceschi et al, 1995a; Decarli et al, 1996) that included a specific question on pizza, in portions per week, one portion corresponding to 200 g. For the present analyses, pizza eating was classified into three categories: noneaters, occasional eaters (one–three portions per month) and regular eaters (≥1 portion of pizza per week; mean amount around 250 g of pizza per week). Frequent eaters were subjects eating ≥2 portions of pizza per week (mean amount around 500 g of pizza per week).

The odds ratios (OR) were derived using unconditional multiple logistic regression, including terms for age, sex, place of birth, education, body mass index (BMI), serum cholesterol, smoking, coffee, alcohol, vegetable, fruit and meat consumption, caloric intake, physical activity, history of hyperlipidaemia, diabetes and hypertension and a family history of AMI in first-degree relatives.

Results

Compared to controls, cases were slightly more educated (multivariate OR was 1.20 for ≥12 vs <7 y), reported less physical activity (OR was 1.39 for low vs high), were more frequently smokers (OR was 2.51 for ≥15 cigarettes per day vs never smokers) and coffee drinkers (OR was 1.46 for ≥21 vs <10 cups per week), and less frequently alcohol drinkers (OR was 0.55 for ≥3 vs <1 drinks per day), had higher BMI (OR was 1.34 for ≥27 vs <24 kg/m2), and reported more frequently a history of hypertension (OR was 1.47), diabetes (OR was 2.72) and a family history of AMI (OR was 4.34 for ≥2 vs 0 first degree relatives). Among other characteristics linked to Mediterranean diet, cases were less frequently consumers of vegetables (OR was 0.79 for ≥11 vs <7 portions per week) and fruit (OR was 0.66 for ≥15 vs <10 portions per week) and had higher caloric intake (OR was 1.46 for higher vs lower quartile).

Compared to nonpizza eaters, the age- and sex-adjusted OR was 0.81 for occasional and 0.59 for regular eaters. Corresponding estimates from multivariate analyses were 0.78 and 0.62, respectively (Table 1). The multivariate OR was 0.44 (95% confidence interval (CI): 0.20–0.97) for ≥2 portions per week.

Table 1 Distribution of 507 cases of acute myocardial infarction (AMI) and 478 controls, and corresponding odds ratios (OR) with 95% confidence intervals (CI), according to pizza consumption (Italy, 1995–1999)

The estimates were similar across strata of age, sex, BMI, cigarette smoking and alcohol drinking, even if the protective effect of pizza seemed to be stronger in current smokers (Table 2). Data were inadequate to investigate diabetics only, but when excluding 74 cases and 30 controls with history of diabetes, the OR for regular pizza eaters was 0.55 (95% CI: 0.36–0.85).

Table 2 Odds ratios (OR), with corresponding 95% confidence intervals (CI), 507 cases of acute myocardial infarction (AMI) and 478 controls, according to pizza consumption (Italy, 1995–1999)

Discussion

The strengths of the study include the validity and reproducibility of the food frequency questionnaire (Franceschi et al, 1995a; Decarli et al, 1996). Moreover, cases and controls were interviewed in the same hospitals and came from the same geographical area, participation was over 95%, and a different recall of pizza intake on the basis of the disease status is unlikely. We were also able to allow in the analyses for a large number of identified potential confounding factors, which however did not explain the inverse association with pizza. The main value of this study, moreover, is given by the originality of the population studied and of the results obtained.

In Italy, most pizza is usually consumed in relatively cheap traditional restaurants called Pizzerias, whereas fast food pizza consumption remains unusual, and the average energy yield of a standard pizza is relatively limited, ie 500–800 kcal. A 100 g of the traditional Italian pizza include approximately 50 g of carbohydrates, 20 g of tomato sauce, 20 g of mozzarella cheese, 4 g of olive oil, 2 g of yeast plus various other toppings (Salvini et al, 1998). Some of the ingredients of pizza have been shown to have a favourable influence on the risk of CVD (Hu & Willett, 2002). We separately considered the association of major ingredients of pizza with AMI risk: although the OR for tomatoes and mozzarella cheese tended to be below unity (Tavani et al, 2002), no consistent association was observed for lycopene or olive oil (Bertuzzi et al, 2002).

In a clinical study based on 25 subjects, pizza consumption, unlike high-fat meals, did not increase the stickiness of the endothelium (Giugliano et al, 2001). Nonetheless, there is no single explanation for the present findings, and pizza may simply represent a general indicator of Italian diet (Gallus et al, 2003; Sesso et al, 2003), that, as other Mediterranean dietary patterns, has been shown to have potential cardiovascular benefits (Verschuren et al, 1995; Trichopoulou et al, 2003). However, allowance for an a priori defined Mediterranean score (Bosetti et al, 2003) did not materially modify the OR for pizza.

In Italy, pizza may also be a general indicator of dietary diversity, that has been shown to be beneficial on the risk of CVD (Kant et al, 1995), as well as several common cancers (Franceschi et al, 1995b; La Vecchia et al, 1997; Fernandez et al, 2000) and all cause mortality (Kant et al, 1993). In our data, pizza consumption was strongly related to a diet diversity score (the average amounts of the diet diversity score were 27.8, 30.8 and 33.5 in non, occasional and regular pizza eaters, respectively; F=49, P<0.0001). However, after further adjustment for variety, the OR for regular pizza eaters did not materially change (OR was 0.63). Likewise, pizza consumption was positively correlated with a number of micronutrients inversely related to the risk of CVD (Tavani et al, 2001; Hu & Willett, 2002; Tavani et al, 2002; Hu, 2003), including n-3 polyunsaturated fatty acids, folate, potassium, antioxidant vitamins and calcium.

These cautions notwithstanding, the present results suggest that pizza consumption is a favourable indicator of risk of AMI in Italy.

References

  1. Bertuzzi M, Tavani A, Negri E & La Vecchia C (2002): Olive oil consumption and risk of non-fatal myocardial infarction in Italy. Int. J. Epidemiol. 31, 1274–1277.

  2. Bosetti C, Gallus S, Trichopoulou A, Talamini R, Franceschi S, Negri E & La Vecchia C (2003): Influence of the Mediterranean diet on the risk of cancers of the upper aerodigestive tract. Cancer Epidemiol. Biomarkers Prev. 12, 1091–1094.

  3. Decarli A, Franceschi S, Ferraroni M, Gnagnarella P, Parpinel MT, La Vecchia C, Negri E, Salvini S, Falcini F & Giacosa A (1996): Validation of a food-frequency questionnaire to assess dietary intakes in cancer studies in Italy. Results for specific nutrients. Ann. Epidemiol. 6, 110–118.

  4. Fernandez E, Negri E, La Vecchia C & Franceschi S (2000): Diet diversity and colorectal cancer. Prev. Med. 31, 11–14.

  5. Franceschi S, Barbone F, Negri E, Decarli A, Ferraroni M, Filiberti R, Giacosa A, Gnagnarella P, Nanni O, Salvini S & La Vecchia C (1995a): Reproducibility of an Italian food frequency questionnaire for cancer studies Results for specific nutrients. Ann. Epidemiol. 5, 69–75.

  6. Franceschi S, Favero A, La Vecchia C, Negri E, Dal Maso L, Salvini S, Decarli A & Giacosa A (1995b): Influence of food groups and food diversity on breast cancer risk in Italy. Int. J. Cancer 63, 785–789.

  7. Gallus S, Bosetti C, Negri E, Talamini R, Montella M, Conti E, Franceschi S & La Vecchia C (2003): Does pizza protect against cancer? Int. J. Cancer 107, 283–284.

  8. Giugliano D, Nappo F & Coppola L (2001): Pizza and vegetables don't stick to the endothelium. Circulation 104, E34–E35.

  9. Hu FB & Willett WC (2002): Optimal diets for prevention of coronary heart disease. JAMA 288, 2569–2578.

  10. Hu FB (2003): Plant-based foods and prevention of cardiovascular disease: an overview. Am. J. Clin. Nutr. 78 (Suppl), 544S–551S.

  11. Kant AK, Schatzkin A, Harris TB, Ziegler RG & Block G (1993): Dietary diversity and subsequent mortality in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Am. J. Clin. Nutr. 57, 434–440.

  12. Kant AK, Schatzkin A & Ziegler RG (1995): Dietary diversity and subsequent cause-specific mortality in the NHANES I epidemiologic follow-up study. J. Am. Coll. Nutr. 14, 233–238.

  13. La Vecchia C, Munoz SE, Braga C, Fernandez E & Decarli A (1997): Diet diversity and gastric cancer. Int. J. Cancer 72, 255–257.

  14. Salvini S, Parpinel M, Gnagnarella P, Maisonneuve P & Turrini A ed. (1998): Banca dati di composizione degli alimenti per studi epidemiologici in Italia. Milan, Italy: Istituto Europeo di Oncologia (IEO). p. 121 (ISBN 88-900271-0-X/WWW. IEO.IT).

  15. Sesso HD, Liu S, Gaziano JM & Buring JE (2003): Dietary lycopene, tomato-based food products and cardiovascular disease in women. J. Nutr. 133, 2336–2341.

  16. Tavani A, Gallus S, Negri E & La Vecchia C (2002): Milk, dairy products, and coronary heart disease. J. Epidemiol. Commun. Health 56, 471–472.

  17. Tavani A, Pelucchi C, Negri E, Bertuzzi M & La Vecchia C (2001): n-3 Polyunsaturated fatty acids, fish, and nonfatal acute myocardial infarction. Circulation 104, 2269–2272.

  18. Trichopoulou A, Costacou T, Bamia C & Trichopoulos D (2003): Adherence to a Mediterranean diet and survival in a Greek population. N. Engl. J. Med. 348, 2599–2608.

  19. Verschuren WM, Jacobs DR, Bloemberg BP, Kromhout D, Menotti A, Aravanis C, Blackburn H, Buzina R, Dontas AS, Fidanza F, Karvonen MJ, Nedeljković S, Nissinen A & Toshima H (1995): Serum total cholesterol and long-term coronary heart disease mortality in different cultures. Twenty-five-year follow-up of the seven countries study. JAMA 274, 131–136.

Download references

Acknowledgements

This work was partially supported by Italian ‘Ministero della Salute’ (Contract no. 177, RF 2001). We thank Dr Patrizia Gnagnarella for assistance on nutritional aspects and Mrs M Paola Bonifacino for editorial assistance.

Author information

Guarantor: S Gallus.

Contributors: SG and CLV had the original idea for the study, and wrote the report with the contribution from AT. CLV contributed to study design and data collection. SG analysed the data.

Correspondence to S Gallus.

Rights and permissions

Reprints and Permissions

About this article

Keywords

  • acute myocardial infarction
  • cardiovascular disease
  • case–control study
  • Mediterranean diet

Further reading