title: Muscle strength in adolescent men and risk of cardiovascular disease events and mortality in middle age: a prospective cohort study.
abstract: BACKGROUND
  Ischemic heart disease and stroke are two severe types of cardiovascular disease (CVD), a major contributor to the global burden of disease. The preventive framework currently includes promotion of both adequate cardiorespiratory and muscular fitness. Although muscle fitness is established as an indicator of health, it is currently unknown whether muscle strength is associated with later CVD independently of cardiorespiratory fitness.
  
  
  METHODS
  We studied 38,588 Swedish men who in 1969 to 1970 (typically aged 18 years) completed compulsory conscription. Using the mean standardized score of three isometric muscle strength tests performed at conscription (hand grip, elbow flexion and knee extension), we categorized the subjects into three groups with the 25th to 75th percentile defining the reference category. We followed the cohort until 2012 for diagnosed CVD events and mortality via national health care registers and the national cause of death register. To estimate hazard ratios (HR) for CVD events (coronary heart disease or stroke) and CVD mortality we used Cox proportional hazard models adjusted for body mass index, smoking, alcohol consumption, cardiorespiratory fitness and socioeconomic status.
  
  
  RESULTS
  Men with high muscle strength in adolescence had a decreased risk of later CVD events (HR 0.88, 95% confidence interval 0.77 to 0.99), whereas we observed no increased risk in men with low muscle strength (0.99, 0.86 to 1.13). However, low muscle strength was associated with increased risk of CVD mortality during middle age (1.31, 1.02 to 1.67).
  
  
  CONCLUSIONS
  Muscle strength in adolescent men is inversely associated with later CVD events and CVD mortality in middle age, independently of cardiorespiratory fitness and other important confounders. Thus, the role of muscle fitness in the prevention and pathogenesis of CVD warrants increased attention.
authors.affiliation: Orthopedics, Clinical Sciences Lund, Lund University, Lund, Sweden. simon.timpka@med.lu.se.
authors.forename: Simon
authors.initials: S
authors.lastname: Timpka
authors.forename: Ingemar F
authors.initials: IF
authors.lastname: Petersson
authors.forename: Caddie
authors.initials: C
authors.lastname: Zhou
authors.forename: Martin
authors.initials: M
authors.lastname: Englund
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000428:Alcohol Drinking / Q000009:adverse effects / Q000401:mortality; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000517:prevention & control; D002320:Cardiovascular Physiological Phenomena; D015331:Cohort Studies; D003327:Coronary Disease / Q000401:mortality; D018737:Hand Strength; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D010809:Physical Fitness; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012143:Respiratory Physiological Phenomena; D012306:Risk; D012907:Smoking / Q000009:adverse effects / Q000401:mortality; D012923:Social Class; D012959:Socioeconomic Factors; D020521:Stroke / Q000401:mortality
references.citation: Med Sci Sports Exerc. 1994 Jul;26(7):857-65
references.pmid: 7934759
references.citation: Stroke. 1997 Sep;28(9):1702-9
references.pmid: 9303012
references.citation: Br Med J (Clin Res Ed). 1988 Apr 9;296(6628):1021-5
references.pmid: 3130122
references.citation: J Gerontol A Biol Sci Med Sci. 1998 Nov;53(6):B415-23
references.pmid: 9823737
references.citation: BMJ. 1998 Jul 25;317(7153):241-5
references.pmid: 9677213
references.citation: J Cardiopulm Rehabil Prev. 2012 Nov-Dec;32(6):351-8
references.pmid: 22885613
references.citation: FASEB J. 1995 Aug;9(11):1091-5
references.pmid: 7649409
references.citation: Am J Cardiol. 1980 Oct;46(4):649-54
references.pmid: 7416024
references.citation: Acta Physiol Scand. 1978 May;103(1):47-51
references.pmid: 665259
references.citation: J Clin Invest. 1990 Nov;86(5):1423-7
references.pmid: 2243122
references.citation: Ups J Med Sci. 1974;79(1):45-50
references.pmid: 4819684
references.citation: Med Sci Sports Exerc. 2007 Jan;39(1):38-43
references.pmid: 17218882
references.citation: Am J Physiol Endocrinol Metab. 2002 Jun;282(6):E1191-6
references.pmid: 12006347
references.citation: J Nutr Health Aging. 2012 Jul;16(7):609-15
references.pmid: 22836701
references.citation: Eur Heart J. 2012 Jul;33(13):1635-701
references.pmid: 22555213
references.citation: JAMA. 1995 Apr 12;273(14):1093-8
references.pmid: 7707596
references.citation: Med Sci Sports Exerc. 2002 May;34(5):740-4
references.pmid: 11984288
references.citation: BMJ. 2010 Sep 09;341:c4467
references.pmid: 20829298
references.citation: BMJ. 2007 Oct 20;335(7624):806-8
references.pmid: 17947786
references.citation: Age Ageing. 2011 Jan;40(1):14-23
references.pmid: 20843964
references.citation: Lancet. 2012 Dec 15;380(9859):2197-223
references.pmid: 23245608
references.citation: Med Sci Sports Exerc. 2010 Sep;42(9):1619-24
references.pmid: 20195176
references.citation: BMJ. 2008 Jul 01;337:a439
references.pmid: 18595904
references.citation: BMJ. 2012 Nov 20;345:e7279
references.pmid: 23169869
references.citation: J Am Coll Cardiol. 2011 May 3;57(18):1831-7
references.pmid: 21527158
references.citation: J Am Coll Cardiol. 2001 Jan;37(1):153-6
references.pmid: 11153730
references.citation: J Appl Physiol (1985). 2011 Mar;110(3):846-53
references.pmid: 21030666
references.citation: Med Sci Sports. 1976 Fall;8(3):179-85
references.pmid: 979566
references.citation: PLoS One. 2011;6(7):e21956
references.pmid: 21760934
references.citation: J Gerontol A Biol Sci Med Sci. 2000 Mar;55(3):M168-73
references.pmid: 10795731
references.citation: BMC Public Health. 2011 Jun 09;11:450
references.pmid: 21658213
references.citation: World Health Organ Tech Rep Ser. 1986;731:1-117
references.pmid: 3085358
references.citation: Int J Epidemiol. 2009 Feb;38(1):110-8
references.pmid: 19033357
references.citation: JAMA. 2009 May 20;301(19):2024-35
references.pmid: 19454641
references.citation: Diabetes Care. 2006 Apr;29(4):895-900
references.pmid: 16567834