Running head: FACTORS THAT INFLUENCE HEART DISEASE

 

 

 

 

 

 

 

 

Factors that influence the risk of death from Heart Disease

Alan A. Jones

U.S. Army-Baylor University Graduate Program

In Health Care Administration

Abstract

The influence of social behavior, race, and pre-existing health conditions on the rate of heart disease related deaths was examined by using statistical hypothesis testing. Data for this research was compiled from the 2003 State Health Profiles. Statistical hypothesis testing revealed a significant relationship between the number of heart disease related deaths per 100,000 people and the percentage of moderate drinkers per state (r = .303, t (48) = 2.21, p<.05), the percentage of African Americans per state (r = .50, t (48) = 4.07, p<.001), and the percentage of adults with diabetes per state (r = .650, t (48) = 5.93, p<.001). This data is vitally important in decreasing the risk of heart disease, which remains the leading cause of death in the United States.

 

 

Factors that influence the risk of death from Heart Disease

Nearly 1 million Americans die from heart attacks and other cardiac emergencies annually (Browner, Jacobs, & Pollack, 1998). The American Heart Association’s (AHA) mission is to reduce the number of deaths and disabilities resulting from heart disease (2005). To support their mission, the AHA conducts and supports extensive research. The AHA notes that the prevalence of heart disease in the United States is higher than all other diseases and estimates that it affects 70,100,000 Americans.

There has been extensive research on the factors that influence the risk of heart disease. Alcohol consumption is one factor that has been examined in over 40 prospective studies in diverse populations. In a 1999 meta-analysis, researchers concluded that moderate alcohol consumption (30 g per day) lowered the risk of coronary heart disease by 24.7% (Rimm, Williams, Fosher, Criqui, & Stampfer). They noted that the decreased risk of heart disease was due to positive changes in lipids and haemostatic factors (Rimm et al.). Although current recommendations in the United States and United Kingdom do not encourage alcohol consumption, based on the findings from numerous studies, moderate alcohol consumption is considered by many to be part of a healthy lifestyle.

The relationship between race and heart disease has also been extensively studied in the past. According to the AHA, last year nearly 106,000 African Americans died from heart disease (2005). According to Clark et al. (2001), African Americans have the highest overall mortality rate from heart disease of any ethnic group in the United States. They (Clark et al.) further add that the prevalence of heart disease risk factors such as hypertension, type 2 diabetes, obesity, cigarette smoking, and physical inactivity is greater in African Americans than in the general population.  These risk factors coupled with delays in identification and treatment of high risk individuals and less access to cardiovascular care puts African Americans at high risk for deaths related to heart disease.

A review of the literature also demonstrates that pre-existing health conditions influence the risk of death from heart disease. In particular, the relationship between heart disease and diabetes is well documented.  According to the American Diabetes Association (2005), diabetes is a disease that affects the body’s ability to produce or respond to insulin, which is needed in order for the body to utilize glucose for energy. According to a study which examined trends in cardiovascular complications of diabetics, adults with diabetes were found to be twice as likely as others to experience a cardiovascular event such as myocardial infarction, coronary heart disease death, or stroke (Fox et al., 2004).

Despite continued efforts to decrease the incidence of heart disease, it remains the leading cause of death for men and women in the United States (Clark et al., 2001). By examining factors related to heart disease, new prevention and treatment strategies can be developed to help aid in the losing battle against this disease. The purpose of this paper is to examine how alcohol consumption, race, and pre-existing health conditions influence heart disease related deaths. 

Method

Data on the relationship between heart disease and alcohol consumption, race, and diabetes was evaluated in an effort to validate the results suggested in the literature. The source of the data was the 2003 State Health Profiles. The Ten Steps for Hypothesis Testing – Functional Form Statistics (Finstuen, 2005) was the format used to analyze the statistical significance of the relationships between the dependent and independent variables.

Heart disease related deaths were studied by using the world population with a sample size (n = 50) of the 50 U.S. states. Heart disease was labeled as the dependent variable (Y) and was operationally defined as heart disease related deaths per 100,000 (CDC, 2003). The independent variables included alcohol consumption, race, and diabetes. Alcohol consumption (X₁) was used as the variable for social behavior and was operationally defined as the percentage of adults 18 years and older per state who reported having 5 or more drinks on one occasion one or more times in the past month. Race (X₂) was the second independent variable and was operationally defined as the percentage of the state population that was African American. Diabetes (X₃) was the third independent variable and was operationally defined as the percentage of adults 18 years and older per state with diabetes. The dependent and independent variables in this study were each continuous measurements.

After defining the dependent and independent variables, hypotheses were formed to examine social behavior, race, and pre-existing health conditions as functional relationships of heart disease. These hypotheses examine if Y = f (X). The first hypothesis (H_a1) states that moderate alcohol use lowers the risk of heart disease related deaths. The null hypothesis (H_o1) states that moderate alcohol use does not have an effect on heart disease related deaths. The second hypothesis (H_a2) states that the higher the percentage of African Americans per state, the higher the percentage of heart disease related deaths per state. The null hypothesis (H_o2) states that an increased percentage of African Americans per state will not have an effect on the percentage of heart disease related deaths per state. The third hypothesis (H_a3) states that the higher the percentage of persons with diabetes per state, the higher the percentage of heart disease related deaths per state. The null hypothesis (H_o3) states that an increased percentage of persons with diabetes per state will not have an effect on the percentage of heart disease related deaths per state. To evaluate the significance of the study the critical probability level was established at     α = .05.

Results

The statistical analysis was calculated using the Statistical Package for the Social Sciences (SPSS).  This analysis included the mean, the standard deviation, the error sum of squares, and Pearson’s r. The descriptive statistics are depicted in Table 1. The mean for each variable reflects the national average. Pearson’s Product-Moment correlation is used because each of the variables contains continuous data. Pearson’s r demonstrates the magnitude and direction of the relationship between the dependent and independent variables. The descriptive analysis is graphically depicted in Figures 1, 2, and 3.

The graph in Figure 1 shows the inverse relationship between moderate alcohol consumption and heart disease related deaths. The data showed that three states were outside of the 95% confidence interval. New York had a high rate of heart disease related deaths, but a low percentage of moderate drinkers. Utah and Hawaii had low rates of heart disease related deaths and a low percentage of moderate drinkers. The graphical information demonstrates that there are possible unique confounders for those three states. The graph in Figure 2 shows a positive relationship between the percentage of African Americans per state and heart disease related deaths. For every 1 increase in Y there was a 1.72 percent increase in X. West Virginia and Oklahoma were both outliers. The graph in Figure 3 shows a positive relationship between diabetes prevalence per state and the number of heart disease related deaths per state. The states of Oklahoma, New York, Alabama, and Hawaii were all outliers. Further research in outlier states on religious, cultural, and socioeconomic practices may reveal the phenomenon which explain their variance.

The inferential statistics were calculated between the dependent and independent variables and are depicted in Table 2. The t Test and the p value demonstrate the relationships’ statistical significances. The statistical hypothesis testing revealed a significant relationship among heart disease related deaths and each of the independent variables. The critical value for each variable was 2.01 for 48 degrees of freedom. For the first variable, heart disease related deaths and alcohol use revealed (r = .30, t(48) = 2.21, p < .05). The data supported the hypothesis and the alternate hypothesis was accepted. For the second variable, heart disease-related deaths and race revealed (r = .57, t(48) = 4.07, p < .05). The data supported the hypothesis and the alternate hypothesis was accepted. For the third variable, heart disease related deaths and diabetes revealed (r = .65, t(48) = 5.93, p < .05). The data supported the hypothesis and the alternate hypothesis was accepted.  Heart disease related deaths are a function of moderate alcohol consumption per state, African American population per state, and diabetes prevalence per state. The shared variance between two variables can be obtained from Pearson’s r. The r value can be squared and subsequently multiplied by 100 to show the percent of shared variance between the two variables. A Venn diagram for each variable is depicted in Figure 4.

Discussion

The statistical analysis of this study supports the findings in the literature review. Each independent variable was found to have a statistically significant relationship to the number of heart disease related deaths. This study highly suggests that heart disease related deaths are a function of social behavior, race, and pre-existing health conditions. Heart disease poses an on-going challenge to the medical community due to the number of factors that can increase the risk or lead to heart disease related deaths. Continued research and statistical analysis will promote alternative treatments that may drastically reduce the number of deaths each year from this disease. Additional studies should be done to determine which factors have the greatest influence on the number one cause of death in the United States.

References

American Diabetes Association. (2005). Diabetes and cardiovascular disease. Retrieved August

25, 2005 from http://www.diabetes.org/diabetes-statistics/heart-disease.jsp

American Heart Association. (2005). Diseases and conditions. Retrieved August 25,

2005, from http://www.americanheart.org/presenter.jhtml?identifier=1200002

Browner, B.D., Jacobs, L.M., Pollack, A.N. (1998). Emergency Care and Transportation of the

Sick and Injured (7th ed.). Sudbury, MA: Jones and Bartlett Publishers, Inc.

Centers for Disease Control and Prevention. 2003 State Health Profiles. Atlanta, GA: US

Department of Health and Human Services, CDC, 2003.

Clark, L.T., Ferdinand, K.C., Flack, J.M., Gavin, J.R., Hall, D.W., Kumanyika, S.K., et al. (2001). Coronary heart disease in African Americans. Heart Disease. 3, 97-108.

Finstuen, K. (2005). Ten steps for hypothesis testing: Functional form statistics. Unpublished manuscript, U.S. Army – Baylor University, Army Medical Department, Ft. Sam Houston, TX.

Fox, C.S., Coady, S., Sorlie, P.D., Levy, D., Meigs, J.B., D’Agostino, R.B., et al. (2004). Trends in cardiovascular complications of diabetes. Journal of the American Medical Association. 292, 2495-2499.

Rimm, E.B., Williams, P., Fosher, K., Criqui, M., Stampher, M.J. (1999). Moderate alcohol intake and lower risk of coronary heart disease: meta-analysis of effects on lipids and haemostatic factors. British Medical Journal. 319, 1523-1528.

 

 

 

Table 1

Descriptive Statistics for Factors that influence the risk of death from Heart Disease           

Variable	M	SD	ESS	r
Heart Disease (Y)	183.32	32.48	51692.57
Alcohol (X1)	14.61	3.38	559.80	.30
African American (X2)	9.90	9.58	4497.04	.57
Diabetes (X3)	5.90	.87	37.10	.65

Note. Data Source: 2003 State Health Profiles

n = 50

 

Table 2

Inferential Statistics for Factors that influence the risk of death from Heart Disease

Variable	t	P
Alcohol (X1)	2.21	.03
African American (X2)	4.07	.00
Diabetes (X3)	5.93	.00

Note. Data Source: 2003 State Health Profiles

n = 50, (df = 48).

 

 

 

 

 

 

Figure 1. Scatter plot and regression line for the relationship between percentage of alcohol consumed and heart disease. H_a1: Y = 225.8 – 2.91X

 

Oklahoma

West Virginia

 

 

 

Figure 2. Scatter plot and regression line for the relationship between percentage of population by state that is African American and heart disease. H_a2: Y = 166.3 + 1.72X

Hawaii

Alabama

New York Oklahoma

 

 

 

 

 

                        

 

Figure 3. Scatter plot and regression line for the relationship between percentage of population with diabetes and heart disease. H_a3: Y = 40.72 + 24.13X

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4. Venn diagram shared variance accounted for the relationship between the dependent variables (Y) and the independent variable (X₁, X₂, X₃). Y = f (X)