KINE 386 Final Study Guide Formulas Attack Rate Attack Rate = (# of people at risk who develop disease / # total at risk) (100%) Case-Fatality Rate Case-Fatality Rate = (# of people who will die from a disease in a specified time range / # of people with the disease) (100%) Incidence Rate Incidence Rate = (# of new disease cases / # of total at risk for disease) (1,000) Prevalence Prevalence = (# of disease cases in a given population/time / population) (1,000) Mortality Rate Mortality Rate = (# of deaths from all causes OR a specific disease in one year in a given population / total population) (100, 000) Relative Risk RR = exposed / unexposed Odds Ratio OR = ad / bc Confidence Interval For RR = Ln (RR) +/- Z x (b/a) / (b+a) + (d/c) / (d+c) For OR = Ln (OR) +/- Z x (1/a) +(1/b) + (1/c) / (1/d) Confidence Interval Correlations RR or OR = 1 exposure has no association RR or OR > 1 exposure is causal RR or OR < 1 exposure is negative, or possibly protective Standard Error (SE) SE = (b/a) / (b+a) + (d/c) / (d+c) Z-Value (Z Score) Z = always 1.96 for a standard distribution Limits Lower Limit = (Ln of RR/OR) – (SE x 1.96/Z) inverse log (ex) of this value = LL Upper Limit = (Ln of RR/OR) + (SE x 1.96/Z) inverse log (ex) of this value = UL Example Calculations In the school cafeteria, 265 students ate hamburger with tainted meat and another 135 ate pizza with some of the same meat on it. By the next day 200 students were ill with food poisoning. What was the attack rate? Attack Rate = (# who get disease / # at risk) (100%) Total Ill = 200 people (given) Total at Risk = 265 + 135 = 400 people Attack Rate = (200 / 400) (100%) Attack Rate = (0.5) (100%) = 50.000% Attack Rate = 50.0% There were 87,000 people who participated in the Nurses’ Health Study and eight years into the program 1300 of them had developed Type II Diabetes. What was the incident rate for TTD? Incidence Rate = (# of new disease cases / # of those at risk for disease) (1,000) Incidence Rate = (1,300 / 87,000) (1,000) Incidence Rate = (0.01494253) (1,000) = 14.94253 Incidence Rate = 14.9 out of every 1,000 nurses developed diabetes In Nevada, there are 2,839,099 people according to the 2014 census. There are 160,056 cases of diabetes. What is the prevalence? Prevalence = (# of disease cases in a population / total population) (1,000) Prevalence = (160,056 / 2,839,099) (1,000) Prevalence = (0.05637563) (1,000) = 56.37653 Prevalence = 56.4 out of every 1,000 Nevadans are diabetic There are 321,368,864 estimated to be living in the U.S. as of July 2015. There is estimated to be 1,400,000 cases of diabetes with an expected 78,000 deaths from diabetes to occur by the end of the year. What are the rates of case-fatality and mortality? Mortality Rate = (# of total deaths / total population) (100,000) Mortality Rate = (78,000 / 321,368,864) (100,000) Mortality Rate = (0.0002427118) (100,000) = 24.27118 Mortality Rate = 24.3 of every 100,000 people will die from diabetes in the US Case-Fatality Rate = (# deaths from a specific disease in a specific time / # of those at risk during specific time) (100%) Case-Fatality Rate = (78,000 / 1,400,000) (100%) Case-Fatality Rate = (0.055714286) (100%) Case-Fatality Rate = 5.6% of those in the US with diabetes will die this year Cohort studies are for gathering information about diseases developing, therefore we compare those exposed to unexposed to measure risk level. Calculate all rates and fill in the 2x2 table with the answers. Then calculate the CI. Subjects over 10 years study Diabetes No disease Totals Incidence rate Relative risk > 40 g sugar per day 856 2,144 3,000 285.3 10.6 < 40 g sugar per day 108 3892 4,000 27.0 *************** Incidence Rate for Exposed (>40g) = (a / a+b) (1,000) Incidence Rate >40g = (856 / 856 + 2,144)(1,000) Incidence Rate >40g = (0.2853333)(1,000) = 285.3333 Incidence Rate >40g = 285.3 out of every 1,000 develops diabetes Incidence Rate for Unexposed (<40g) = (c / c+d)(1,000) Incidence Rate <40g = (108 / 108 + 3892)(1,000) Incidence Rate <40g = (0.027)(1,000) = 27.000 Incidence Rate <40g = 27.0 out of every 1,000 develops diabetes Relative Risk (RR) = exposed / unexposed RR = 285.3 / 27.0 = 10.56667 RR = 10.6 Confidence Interval Ln (RR) Ln (10.6) = 2.3608540 Ln (RR) = 2.361 SE = (b/a) / (b+a) + (d/c) / (d+c) SE = ([2144 / 856] / [2144 + 856) + [3892 / 108] / [3892 + 108]) SE = 0.00834891 + 0.00900259 = 0.099217 SE = 0.1 CI = Ln(RR) +/- (Z)(SE) Lower Limit = Ln(10.6) – ([1.96][0.1]) Upper Limit = Ln(10.6) + ([1.96][0.1]) Lower Limit = 2.361 – 0.196 = 2.165 Upper Limit = 2.361 + 0.196 = 2.557 Lower Limit = e(2.165) Upper Limit = e(2.557) Lower Limit = 8. 71460192 Upper Limit = 12.897068 Lower Limit = 8.71 Upper Limit = 12.9 Since the RR is above 1, and the CI is between 8.71 and 12.9, we can determine that eating more than 40 grams of sugar a day is causal to diabetes. Case-Control studies are to identify what the sick subjects were exposed to that may have a causal effect. The cases are compared to controls (healthy subjects) who were also exposed. However, there will always be cases and controls who were not exposed as part of the comparison because one risk factor does not generally make everyone ill. Calculate all rates of exposure, the odds that the exposure lead to the disease, and explain your answer. Subjects Cases of High Cholesterol Controls Red meat 5x week 800 2,000 Red meat 1x week 60 800 Proportion Exposed = (a / a+c) (100%) Proportion Exposed = (800 / 800 + 60) (100%) Proportion Exposed = (0.93023256) (100%) = 93.023256% Proportion Exposed = 93.0% of cases ate red meat 5x a week and developed high cholesterol. Proportion Unexposed = (b / b+d)(100%) Proportion Unexposed = (2000 / 2000 + 800) (100%) Proportion Unexposed = (0.714286)(100%) = 71.4286% Proportion Unexposed = 71.4% of controls ate red meat 5x a week but did not develop high cholesterol. Odds Ratio (OR) = ad / bc OR = (800 x 800) / (2,000 x 60) OR = 640,000 / 120,000 = 5.3333 OR = 5.3 Confidence Interval Ln (OR) Ln (5.3) = 1.6677068 Ln (RR) = 1.6677 SE = (1/a) + (1/b) + (1/c) + (1/d) SE = (1/800) + (1/2000) + (1/60) + (1/800) SE = 0.00125 + 0.0005 + 0.00125 + 0.01667 SE = 0.01967 = 0.14024978 SE = 0.14 CI = Ln(OR) +/- (Z)(SE) Lower Limit = Ln(5.3)– ([1.96][0.14]) Upper Limit = Ln(5.3) + ([1.96][0.14]) Lower Limit = 1.6677 – 0.2744 = 1.3933 Upper Limit = 1.6677 + 0.2744 = 1.9421 Lower Limit = e(1.3933) Upper Limit = e(1.9421) Lower Limit = 4.0281209 Upper Limit = 6.973379 Lower Limit = 4.03 Upper Limit = 6.97 We can say that since the OR is 5.3 and the CI is 4.03 and 7 and all are above 1, that there is a causal relationship between eating red meat 5x/week and the development of high cholesterol. However there were a large number of controls who also ate red meat 5x per week and did not have cholesterol issues, so there must be some other effect occurring that must be considered, for example the controls may be more active, there may be an inherited factor or perhaps the cases have a secondary risk factor that together with the red meat is highly causal such as smoking or high alcohol use. Things to Know What mental disorders are common by age 18? Phobias and ADD developed by 1st grade Age 12 50% of anxiety and impulse control cases are developed o Age 11-12 median age of self-medication experimentation for these conditions Age 14 50% of mentally ill individuals are substance abusers o Age 24 75% of mentally ill individuals are substance abusers High School Age depression What mental health issues are more common in women vs. men? Women Men Anxiety (29.9% of all women) Impulse Control (25% of all men) Mood Disorders (21.4% of all women) Substance Abuse (35.5% of all men) What are some genetic markers of elite athletes? Athlete/Exercise Considerations o 45% of muscle fiber type is genetic o ACTN3 capability Promote formation of fast-twitch muscle Alter glucose metabolism in response to training Minimize damage from eccentric contractions o ACE Activity ACE I (Insertion) lower ACE activity = slow twitch muscle fibers = endurance athletes ACE D (Deletion) higher ACE activity = fast twitch muscle fibers = power athletes and/or sprinters Criteria for Choosing Athletes o Parents height and muscularity o Blood and muscle type More white blood cells power More red blood cells endurance o Overall general strength o How the skin pulls away from the muscle o Jumping height, distance, reversal speed, and extreme flexibility o Psychological attitude o Physical reproductive characteristics Girls small breasts, square jaw Boys testicle size o High IQ o Kinesthetic ability What are the most common injury sites? Most Common Injury Sites Women Men KNEE 22.3% (specifically higher ACL) 23.2% FOOT 15.7% 12.9% BACK 10.3% 10.6% Common Injuries during Physical Activity o Fractures/dislocations o Sprains/strains Sprain: injury at muscle or ligament Strain: injury at tendon o Cuts/bruises 1.5% of the population is injured via physical activity o Sport related injuries make up 23-25% of all emergency room visits for people between ages 5-24 What practices reduce Delayed Onset Muscle Soreness? Cryotherapy 3 minute whole body immersion in very cold environment Stretching to release muscle tension Massage o Reduces pain during stretch, sensitivity, and pain perception Chiropractic Care o Pain and disability significantly reduced compared to MD visits Complimentary Medicine (however, no evidence when compared with placebos) o Arnica o Vitamin C 200mg twice a day for 2 days o Vitamin C and E 30 days prior taking 500mg daily Allowed for greater power and less fatigue, but not full DOMS reduction o Chiropractic Care Pain and disability significantly reduced compared to MD visits Understand the phases of the immune system. Phases of Immune Response o First Innate Skin Resident phagocytes Killer blood proteins o Secondary Induced Responses (occurs in a loop) Inflammation Phagocytes and natural killer cells migrate Cytokine hormone released When abnormal, cytokine storm can occur (cytokine hormone will not shut off, causing congested cells and tissue damage) o Third Phase Normal Adaptive response of immunity What are the jobs of various hormones and proteins that fight bacteria and viruses from where they initiate? Skin and Intestinal Tract o Phagocytic cells find, attack, and kill antigens o Blood proteins that kill bacteria (e.g. E. coli) Blood o Antibodies produced after antigen exposure to attempt to prevent pathogen growth o Leukocytes (WBCs): attack and kill antigens, tumors, and viruses Come from bone marrow and circulate in blood, lymph, and spleen Leukocytosis: increase in number of WBCs when sick, indicating infection o B-Cells: produce antibodies during initial infection o T-Cells: help kill or suppress growth of ‘bad’ cells o Monocytes: multi-functioned cells that travel in the blood and attach themselves to tissues Absorb wastes and harmful microorganisms Regulate clotting and antigen cells Become macrophages (giant infection eaters) o Granulocytes: migrate to sources of inflammation and ingest bacteria Abundant in the blood; is what makes up the contents of pus Spleen o Natural Killer (Granular Cells): kill tumor cells and viruses without prior exposure Cytokines: multi-functioned proteins produced by the cells o Communicate, escort, bind to, and activate cells in the body o Boost resistance of immunity o Impede division of unhealthy or abnormal cells o Induce acute-phase response: fever, fatigue, loss of appetite, nausea, etc., when sick Benefits of Being a Trained Athlete o Natural killer cells increase in the blood even weeks after training o Trained subjects have higher levels of leukocytes, granulocytes, and natural killer cells o C-reactive proteins reduced in endurance athletes (inflammatory marker) Levels are higher in over-fat or sedentary subjects