Editorial on the paper by Leung et al. “Associations between body-mass index and second-hand smoke exposure and stroke recurrence in Chinese patients in Xi’an, Shantou, and Chongqing: a multicentre cross-sectional survey”
Editorial

Editorial on the paper by Leung et al. “Associations between body-mass index and second-hand smoke exposure and stroke recurrence in Chinese patients in Xi’an, Shantou, and Chongqing: a multicentre cross-sectional survey”

Rascha von Martial, Sebastian Bellwald, Urs Fischer, Marcel Arnold, Hakan Sarikaya

Department of Neurology, Inselspital, University Hospital Bern and University of Bern, Bern, Switzerland

Correspondence to: Hakan Sarikaya, MD, Associate Professor, Department of Neurology, University Hospital of Berne, Freiburgstrasse 4, CH - 3010 Bern, Switzerland. Email: hakan.sarikaya@insel.ch.

Provenance: This is a Guest Editorial commissioned by the Editor-in-Chief Baoli Zhu (Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China).

Comment on: Leung DY, Wong EM, Chan AW, et al. Associations between body-mass index and second-hand smoke exposure and stroke recurrence in Chinese patients in Xi'an, Shantou, and Chongqing: a multicentre cross-sectional survey. Lancet 2016;388 Suppl 1:S50.


Received: 15 March 2017; Accepted: 16 March 2017; Published: 07 April 2017.

doi: 10.21037/jphe.2017.03.13


The global burden of stroke is significant with an annual incidence of more than 15 million first-ever strokes and nearly six million deaths every year. Considering demographic changes with ageing population, further increase of stroke rates is expected (1,2). Moreover, stroke also increasingly affects younger patients—recent data suggest that about 15% of all patients with stroke are younger than age of 65 years (3). The World Health Organization calls stroke therefore the incoming epidemic of the 21st century. Lifestyle modification is of particular interest for stroke prevention, as age-adjusted incidence of stroke has decreased by up to 42% in developed countries within the last 30 years, whereas an increase by more than 100% has being reported in developing countries (4). Recent studies suggest that up to 75% of global stroke burden is attributable to modifiable behavioural factors such as smoking, poor diet and low physical activity (5). The two latter factors are associated with obesity, which is also an established risk factor for the development of vascular diseases such as stroke. It has been shown that each unit increase of BMI was associated with a significant 6% increase in the adjusted relative risk of stroke (6), the association between BMI and risk of ischemic stroke was linear (7), similar in men and women and regardless of race (8). Tobacco smoking is another major independent risk factor for ischemic stroke (9). Recent data show that even second-hand smoking is known to raise the relative stroke risk by about 30% (10).

In this study, Leung and colleagues assessed the relationship between body mass index (BMI), second-hand smoke (SHS) exposure and risk of stroke recurrence in 503 stroke patients. They included surveys between April 2012 and December 2013. A total of 202 patients (40%) suffered stroke recurrence. Logistic regression analysis showed a higher rate of recurrent stroke in patients with underweight (BMI <18.5 kg/m2) whereas patients with overweight (BMI ≥24 kg/m2) had similar risk for stroke recurrence compared to patients with normal weight. There was no association between SHS exposure at home or at work with recurrence of stroke. They concluded that optimal weight management should take essential part of secondary prevention and stroke rehabilitation.

This study indicates that physicians should also consider underweight and malnutrition as significant challenge in stroke patients. Severe underweight has been shown to be an independent significant risk factor for intracranial hemorrhages and cerebral microbleeds, even after adjustment for age, smoking, and pre-existing illness (11). Stroke patients with hypoalbuminemia at admission suggesting malnutrition had an increased risk of infective complications and poor functional outcome (12). Malnutrition has a high prevalence of 20–60% in patients on hospital admission, whereas underweight is a main indicator of malnutrition (13). Both underweight and malnutrition correlate with higher risk for mortality (14,15). The high rate of 40% stroke recurrence in the current study by Leung et al. is unusual and remarkable. These numbers are controversial to recent studies describing stroke recurrence rates of 1.2–3.3% after one month and 9.2–14.1% after two years (16). This may be due to the fact that the underlying time period is not defined in the present study. Furthermore, we lack data on baseline characteristics of study population and the number of patients may be too low for a firm conclusion. Nevertheless, patients with underweight and/or malnutrition may be especially prone to adverse outcomes given the high catabolic stress in the acute phase of stroke. Frequency of malnutrition in these stroke patients and their outcome would be valuable to define to current burden and to plan nutritional intervention studies accordingly in this high risk-group.

On the other hand, most observational data indicate a survival benefit of obese patients after stroke which is called “obesity paradox”. However, a number of methodological concerns exists (17). No obesity paradox was observed in patients after intravenous thrombolysis (18,19). There is a need for well-designed and adequately-powered randomized controlled trials assessing the effects of weight reduction on stroke occurrence and recurrence in obese patients. Though conflicting results from observational studies reporting better stroke outcomes in obese patients or those with current smoking, optimal weight management and smoking cessation should still be strictly recommended to patients at stroke risk (20).


Acknowledgements

None


Footnote

Conflicts of Interest The authors have no conflicts of interest to declare


References

  1. Di Carlo A. Human and economic burden of stroke. Age Ageing 2009;38:4-5. [Crossref] [PubMed]
  2. Howard G, Goff DC. Population shifts and the future of stroke: forecasts of the future burden of stroke. Ann N Y Acad Sci 2012;1268:14-20. [Crossref] [PubMed]
  3. Lasek-Bal A, Gąsior Z. Cardiovascular diseases in patients 65 years and younger with non-cardiogenic stroke. Arch Med Sci 2016;12:556-62. [Crossref] [PubMed]
  4. Hankey GJ. Nutrition and the risk of stroke. Lancet Neurol 2012;11:66-81. [Crossref] [PubMed]
  5. Feigin VL, Mensah GA, Norrving B, et al. Atlas of the Global Burden of Stroke (1990-2013): The GBD 2013 Study. Neuroepidemiology 2015;45:230-6. [Crossref] [PubMed]
  6. Kurth T, Gaziano JM, Berger K, et al. Body mass index and the risk of stroke in men. Arch Intern Med 2002;162:2557-62. [Crossref] [PubMed]
  7. Strazzullo P, D'Elia L, Cairella G, et al. Excess body weight and incidence of stroke: meta-analysis of prospective studies with 2 million participants. Stroke 2010;41:e418-26. [Crossref] [PubMed]
  8. Yatsuya H, Folsom AR, Yamagishi K, et al. Race- and sex-specific associations of obesity measures with ischemic stroke incidence in the Atherosclerosis Risk in Communities (ARIC) study. Stroke 2010;41:417-25. [Crossref] [PubMed]
  9. Peters SA, Huxley RR, Woodward M. Smoking as a risk factor for stroke in women compared with men: a systematic review and meta-analysis of 81 cohorts, including 3,980,359 individuals and 42,401 strokes. Stroke 2013;44:2821-8. [Crossref] [PubMed]
  10. Malek AM, Cushman M, Lackland DT, et al. Secondhand Smoke Exposure and Stroke: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study. Am J Prev Med 2015;49:e89-97. [Crossref] [PubMed]
  11. Yamada S, Satow T, Fukuda A, et al. Severe underweight and cerebral microbleeds. J Neurol 2012;259:2707-13. [Crossref] [PubMed]
  12. Gariballa SE, Parker SG, Taub N, et al. Influence of nutritional status on clinical outcome after acute stroke. Am J Clin Nutr 1998;68:275-81. [PubMed]
  13. Kondrup J, Allison SP, Elia M, et al. ESPEN guidelines for nutrition screening 2002. Clin Nutr 2003;22:415-21. [Crossref] [PubMed]
  14. Romero-Corral A, Montori VM, Somers VK, et al. Association of bodyweight with total mortality and with cardiovascular events in coronary artery disease: a systematic review of cohort studies. Lancet 2006;368:666-78. [Crossref] [PubMed]
  15. Wang ZJ, Zhou YJ, Galper BZ, et al. Association of body mass index with mortality and cardiovascular events for patients with coronary artery disease: a systematic review and meta-analysis. Heart 2015;101:1631-8. [Crossref] [PubMed]
  16. Feng W, Hendry RM, Adams RJ. Risk of recurrent stroke, myocardial infarction, or death in hospitalized stroke patients. Neurology 2010;74:588-93. [Crossref] [PubMed]
  17. Oesch L, Tatlisumak T, Arnold M, et al. Obesity paradox in stroke - Myth or reality? A systematic review. PLoS One 2017;12:e0171334. [Crossref] [PubMed]
  18. Sarikaya H, Elmas F, Arnold M, et al. Impact of obesity on stroke outcome after intravenous thrombolysis. Stroke 2011;42:2330-2. [Crossref] [PubMed]
  19. Sarikaya H, Arnold M, Engelter ST, et al. Outcome of intravenous thrombolysis in stroke patients weighing over 100 kg. Cerebrovasc Dis 2011;32:201-6. [Crossref] [PubMed]
  20. Sarikaya H, Ferro J, Arnold M. Stroke prevention--medical and lifestyle measures. Eur Neurol 2015;73:150-7. [Crossref] [PubMed]
doi: 10.21037/jphe.2017.03.13
Cite this article as: von Martial R, Bellwald S, Fischer U, Arnold M, Sarikaya H. Editorial on the paper by Leung et al. “Associations between body-mass index and second-hand smoke exposure and stroke recurrence in Chinese patients in Xi’an, Shantou, and Chongqing: a multicentre cross-sectional survey”. J Public Health Emerg 2017;1:37.

Refbacks

  • There are currently no refbacks.