The Effect of Heart Disease Differential Mortality Rate on Cholesterol Distribution

  • Ali Zare Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran.
  • Mahmood Mahmoodi Mail Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran.
Keywords:
Cholesterol distribution, Differential mortality, Heart diseases, Weibull hazard rate

Abstract

In a good deal of studies cholesterol distribution, as a risk factor, demonstrates a special treatment towards age so that it shows an upward trend up to an age group and exhibits a downward trend for older age brackets thereafter. To investigate this phenomenon, two general points of view are presented. First, this issue may occur naturally for many subjects and it may be due to natural treatment of cholesterol variable with age. Second, it could be related to differential mortality, i.e. mortality changes in different age groups. In other words, it can be said that higher levels of cholesterol are relevant to younger-age mortality rate. Constructing a parametric model based on Weibull distribution, the association of this phenomenon with differential mortality was investigated. This study revealed that the effect of differential mortality on cholesterol distribution in the age groups younger than 65 were insignificant and it could partly be justifiable just in older age groups because it involves 35% changes in the 85-95 age groups. Thus, the differential mortality justifies just a part of cholesterol changes and other parts are due to intrinsic changes of cholesterol variable with time.

References

Ezzati M, Lopez AD, Rodgers A, Murray CJ. Comparative quantification of health risks. Global and regional burden of disease attributable to selected major risk factors Geneva: World Health Organization. 2004.

Collaboration APCS. Cholesterol, coronary heart disease, and stroke in the Asia Pacific region. International journal of epidemiology. 2003;32(4):563-72.

Volpato S, Zuliani G, Guralnik JM, Palmieri E, Fellin R. The inverse association between age and cholesterol levels among older patients: the role of poor health status. Gerontology 2001 47(1):35-45.

Manolio TA, Cushman M, Gottdiener JS, Dobs A, Kuller LH, Kronmal RA; CHS Collaborative Research Group. Predictors of falling cholesterol levels in older adults: the cardiovascular health study. Annals of Epidemiology 2004;14(5):325-31.

Schalk BW, Visser M, Deeg DJ, Bouter LM. Lower levels of serum albumin and total cholesterol and future decline in functional performance in older persons: the Longitudinal Aging Study Amsterdam. Age Aging 2004;33(3):266-72.

Goldstein JL, Hazzard WR, Schrott HG, Bierman EL, Motulsky AG. Hyperlipidemia in coronary heart disease 1. Lipid levels in 500 survivors of myocardial infraction. J Clin Invest 1973;52(7):1533-15.

Schatz IJ, Masaki K, Yano K, Chen R, Rodriguez BL, Curb JD. Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study. Lancet 2001;358(9279):351-5.

Casiglia E, Mazza A, Tikhonoff V, Scarpa R, Schiavon L, Pessina AC. Total cholesterol and mortality in the elderly. Journal of Internal Medicine 2003;254(4):353-62.

Ko DT, Mamdani M, Alter DA. Lipid-lowering therapy with statins in high-risk elderly patients. JAMA 2004;291(15):1864-70.

Law MR, Wald NJ, Thompson SG. By how much and how quickly does reduction in serum cholesterol concentrationlower risk of ischaemic heart disease? British Medical Journal 1994;308(6925):367–72.

Law MR, Wald NJ, Wu T, Hackshaw A. Bailey A Systematic underestimation of association between serum cholesterol concentration and ischaemic heart disease in observational studies: data from the BUPA study. BMJ 1994;308(6925):363–6.

Lewington S, MacMahon S. Blood pressure, cholesterol, and common causes of death: a review. Prospective studies collaboration. AM J Hypertension 1999;12(10 Pt 2):S96-8.

Neaton JD, Wentworth D. Serum cholesterol, blood pressure, cigarette smoking, and death from coronary heart disease overall findings and differences by age for 316099 white men. Arch Int Med 1992;152(1):56-64.

McGilchrist CA, Simpson JM. Effect of differential mortality rate on risk-variable distribution. Mathematical Biosciences. 1979;43(3):173-80.

Royston P, Sauerbrei W. Multivariable model-building. A pragmatic approach to regression analysis based on fractional polynomials for modelling continuous variables. Wiley-Blackwell, Chichester; 2008.

Delavari A, Alikhani S, Alaedini F. A national profile of non-communicable disease risk factors in the IR of Iran. Ministry of Health, Deputy to Health Directory, CDC. 2005.

Braunwald’s heart disease, A textbook of cardiovascular medicine. 7th edition, Elsevier saunders; 2005.

Fuster V, Alexander RW, O'Rourke RA, Roberts R, King SB, Wellens JJ. Hurst's the Heart, 2-Vol Set. McGraw-Hill Professional Publishing 2000.

American Heart Association: Heart and stroke statistical update. Dallas; 2003.

World Health report: reducing risks, promoting healthy life-geneva, World Health Organization 2002.

How to Cite
1.
Zare A, Mahmoodi M. The Effect of Heart Disease Differential Mortality Rate on Cholesterol Distribution. Acta Med Iran. 51(9):599-603.
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