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Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study

BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e4026 (Published 26 June 2012) Cite this as: BMJ 2012;344:e4026
  1. Pagona Lagiou, professor12,
  2. Sven Sandin, scientist3,
  3. Marie Lof, scientist34,
  4. Dimitrios Trichopoulos, professor25,
  5. Hans-Olov Adami, professor23,
  6. Elisabete Weiderpass, professor367
  1. 1Department of Hygiene, Epidemiology and Medical Statistics, University of Athens Medical School, 75 M. Asias Street, Goudi, GR-115 27, Athens, Greece
  2. 2Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
  3. 3Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, SE-171 77, Stockholm, Sweden
  4. 4Department of Clinical and Experimental Medicine, University of Linköping, SE-58185 Linköping, Sweden
  5. 5Bureau of Epidemiologic Research, Academy of Athens, Athens, GR-106 79, Greece
  6. 6Cancer Registry of Norway, Montebello, N-0310, Oslo, and Department of Community Medicine, University of Tromso, Tromso, Norway
  7. 7Folkhälsan Research Center, Samfundet Folkhälsan, Helsinki, Finland
  1. Correspondence to: P Lagiou pdlagiou{at}med.uoa.gr
  • Accepted 28 April 2012

Abstract

Objective To study the long term consequences of low carbohydrate diets, generally characterised by concomitant increases in protein intake, on cardiovascular health.

Design Prospective cohort study.

Setting Uppsala, Sweden.

Participants From a random population sample, 43 396 Swedish women, aged 30-49 years at baseline, completed an extensive dietary questionnaire and were followed-up for an average of 15.7 years.

Main outcome measures Association of incident cardiovascular diseases (ascertained by linkage with nationwide registries), overall and by diagnostic category, with decreasing carbohydrate intake (in tenths), increasing protein intake (in tenths), and an additive combination of these variables (low carbohydrate-high protein score, from 2 to 20), adjusted for intake of energy, intake of saturated and unsaturated fat, and several non-dietary variables.

Results A one tenth decrease in carbohydrate intake or increase in protein intake or a 2 unit increase in the low carbohydrate-high protein score were all statistically significantly associated with increasing incidence of cardiovascular disease overall (n=1270)—incidence rate ratio estimates 1.04 (95% confidence interval 1.00 to 1.08), 1.04 (1.02 to 1.06), and 1.05 (1.02 to 1.08). No heterogeneity existed in the association of any of these scores with the five studied cardiovascular outcomes: ischaemic heart disease (n=703), ischaemic stroke (n=294), haemorrhagic stroke (n=70), subarachnoid haemorrhage (n=121), and peripheral arterial disease (n=82).

Conclusions Low carbohydrate-high protein diets, used on a regular basis and without consideration of the nature of carbohydrates or the source of proteins, are associated with increased risk of cardiovascular disease.

Footnotes

  • We thank Pouran Almstedt for her help in data management.

  • Contributors: HOA and EW were involved in the conception and design of the initial cohort. PL, HOA, and DT were involved in the conception and design of the study. SS, PL, and DT did the data analysis. ML and PL were responsible for nutritional epidemiology. All authors were involved in interpretation of data. PL, SS, and DT drafted the manuscript, and all authors critically revised it for important intellectual content. All authors approved the final version to be published. EW is the guarantor.

  • Funding: The study was supported by grants from the Swedish Cancer Society and the Swedish Research Council. The study sponsors were not involved in the study design and the collection, analysis, and interpretation of data, nor the writing of the article or the decision to submit it for publication. The authors were independent from the study sponsors.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The study was approved by the Swedish Data Inspection Board and the regional ethical committee.

  • Data sharing: No additional data available.

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