Jump to comment:

• Respiratory muscle strength and vascular risk: the potential role of diabetes
  Filippo Luca Fimognari
  Published on: 12 May 2005

• Published on: 12 May 2005

  Respiratory muscle strength and vascular risk: the potential role of diabetes

  • Filippo Luca Fimognari, Medical Doctor
  • Other Contributors:
    • Luigi Ferri, Alfredo Cesario, Massimo Fini

  Dear Editor,

  In a recent issue of Thorax, van der Palen et al. [1] published a study showing that a reduced Maximal Inspiratory Pressure (MIP), a measure of diaphragmatic inspiratory muscle strength, is a risk factor for incident myocardial infarction and death from cardiovascular disease in a population of subjects without previously reported cardiovascular events. We believe this result has a strong impact on...

  Show More

  Dear Editor,

  In a recent issue of Thorax, van der Palen et al. [1] published a study showing that a reduced Maximal Inspiratory Pressure (MIP), a measure of diaphragmatic inspiratory muscle strength, is a risk factor for incident myocardial infarction and death from cardiovascular disease in a population of subjects without previously reported cardiovascular events. We believe this result has a strong impact on the understanding of the increased cardiovascular risk in persons with impaired lung function.

  An "impaired lung function", as indicated by low forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and peak expiratory flow (PEF), has been repeatedly associated with a higher risk of cardiovascular morbidity and mortality, independently of visceral obesity and smoking.[2] Insulin-resistance [3] and systemic inflammation [4] qualify these subjects and potentially account for the atherothrombotic risk. Moreover, several studies have proven a poor lung function in the vast majority of patients affected by diabetes mellitus.[5]

  However, the generic condition of "impaired lung function" encompasses two particular respiratory alterations: a restrictive dysfunction, characterised by a homogenous decrease of FVC, FEV1 and PEF [6], and an obstructive pattern, with a predominant FEV1 fall and low FEV1/FVC ratio, typical of chronic obstructive pulmonary disease (COPD).[7] Recent epidemiological data suggest that in restrictive subjects the level of systemic inflammation [8] and the risk of incident death [7] are comparable to what observed in patients with moderate COPD. Conversely, restrictive subjects, but not COPD patients, are more likely to develop diabetes mellitus [9,10], suggesting that undetermined metabolic abnormalities specifically characterise patients with a restrictive dysfunction. It is therefore likely that COPD and restrictive syndrome predispose to vascular disease through partly different mechanism/s, that should be further investigated.

  The study of van der Palen et al. [1] is important because it focuses on a particular aspect of respiratory pathophysiology, the reduction of diaphragmatic inspiratory muscle strength, which may underlie the restrictive syndrome and have metabolic origin. However, the authors did not mention diabetes and impaired glucose tolerance (both included among the descriptive variables) as potential confounding factors. Indeed, because of the strong association between insulin resistance [3] and diabetes [9,10] with the restrictive syndrome, the statistical impact of pre-diabetes and diabetes in the relation between MIP and vascular events should be better clarified by the authors.

  References

  1. van der Palen J, Rea TD, Manolio TA, et al. Respiratory muscle strength and the risk of incident cardiovascular events. Thorax 2004; 59: 1063-67.

  2. Hole DJ, Watt GC, Davey-Smith G, et al. Impaired lung function and mortality risk in men and women: findings from the Renfrew and Paisley prospective population study. BMJ 1996; 313: 711-5.

  3. Lawlor DA, Ebrahim S, Davey-Smith G. Association of measures of lung function with insulin resistance and type 2 diabetes: findings from the British Women’s Heart and Health Study. Diabetologia 2004; 47: 195-203.

  4. Engstrom G, Lind P, Hedblad B, et al. Lung function and cardiovascular risk. Relationship with inflammatory-sensitive plasma protein. Circulation 2002; 106: 2555-60.

  5. Lange P, Groth S, Kastrup J, et al. Diabetes mellitus, plasma glucose and lung function in a cross-sectional population study. Eur Resp J 1989; 2:14-9.

  6. Mannino DM, Buist AS, Petty TL, et al. Lung function and mortality in the United States: data from the First National Health and Nutrition Examination Survey follow up study. Thorax 2003; 58: 388-93.

  7. National Institutes for Health. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Publication No 2701. Bethesda: National Institutes for Health, 2001 (2004 update).

  8. Mannino DM, Ford ES, Redd SC. Obstructive and restrictive lung disease and markers of inflammation: data from the Third National Health and Nutrition Examination. Am J Med 2003: 114: 758-762.

  9. Ford ES, Mannino DM. Prospective association between lung function and the incidence of diabetes. Findings from the National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study. Diabetes Care 2004; 27: 2966-70.

  10. Fimognari FL, Scarlata S, Pastorelli R, et al. Restrictive ventilatory dysfunction and dyspnea in elderly subjects. Am J Med 2005; November, in press.

  Show Less

  Conflict of Interest:
  None declared.

  • Back to top