Landmark Epidemiological Studies Flashcards
Framingham HEart Study
Originated to address non-infectious problems
-1940s-1950s cardiovascular disease became more prevalent
What kind of study is Framingham Heart study
Prospective cohort study
The study population in Framingham heart study
5200 persons between 30-52 WITHOUT cardiovascular disease were examined and potential risk factors recorded
Later on in the Framingham Heart study
- children and spouses were also given similar evaluation
- later on, an OMNI COHORT, reflected more diverse population
The Framingham heart study has produced _______ in leading medical journals
1200 articles
Generates in Framingham
3rd generation-grandchildren of original cohort
2nd group of Omni participants
Much of what we know about _____ come from Framingham
Risk factors for CVD
- HTN, cholesterol, HDL/LDL, trigs, smoking, DM, physical inactivity
- age, gender, psychosocial factors
Framingham Heart study: relative risk for CHD for individual risk factors
Smoking had a greater relative risk for CHD
All between 1 and 2x relative risk
Measure of incidence
Framingham HEart Study: multiple risk factors
The more risk factors you have, the greater the odds of CHD
If you have all of the risk factors, you have a 14x odds ratio of having CHD
HDL and LDL: Framingham
The lowest risk
- least LDL and the highest HDL
- RR is less than 1, its protective
Highest risk
- lowest HDL and highest LDL
- RR is 3
Framingham: DM and CHD
Among men and women, the number of deaths from CHD among diabetics was much higher
- men: 2x deaths in DM
- women: 4x as many deaths in DM
DM is a risk factor death and directly related to CHD
Framingham Eye Study
2600 of the 4000 still living members 52-85 were given eye exam and looked at PREVALENCE of eye diseases in this population
-gave us some info on the conditions on this cohort
Framingham and dementia
- although PREVALENCE is increasing due to longer living, INCIDENCE was found to have decreased. This is consistent with other recent studies
- looked at 4 EPOCHS
- incidence increasingly DECLINED in each epoch compared to baseline
Framingham and dementia: caveat
- decrease in incidence of dementia was only seen in individuals with at least a high school diploma
- the reduction in cardiovascular risk factors (except diabetes and obesity) may explain some, not all of the results
- stable or decreased incidence of dementia has been noted in OTHER PARTS OF THE WORLD. Reason-improvements in living conditions, health care, eduction
BEaver Dam health outcomes study
- PROSPECTIVE COHORT STUDY of health status and health related quality of life in adults
- random sample of adults, inital age range 45-89; mean 64
BEaver dam eye study
- examined PREVALENCE AND INCIDENCE of AMD, cataract, DR, glaucoma and other eye diseases
- 5000 people had baseline exams in early 90s
- 5,10,15,20, and now 25 year follow up
Publications from beaver dam eye study
360
Modifiable risk factors and Disease: beaver dam eye study
Doing link between modifiable risk factors and disease
- cigarette smoking and both cataracts and AMD
- lutein intake and lower risk of cataract
Systems developed to photograph cataracts and AMD, including a standardized scale
Beaver dam and drusen
-connection between retinal drusen and RPE loss with progression to late stage AMD
Currently studying incidence of AMD in relation to
- modifiable risk factors
- glycooxidative stress
- inflammation
- atherosclerosis
Nurses health study
- ongoing PROSPECTIVE COHORT STUDY began in 70s-cardiovascular disease, cancer, DM, women’s health, lifestyle
- RNs were selected to be followed prospectively
- inital phase-122,000 nurses
- every two years, follow up exam AND QUESTIONNAIRE FOR HEALTH RELATED TOPICS including smoking, hormone use, menopausal status, diet
Women and physical activity: nurse study
The more physical activity women have, the less RR for DR
As physical activity increases, RR decreases
Physical activity is protective against DM, RR is below 0
Baltimore eye survey
- CROSS SECTIONAL study conducted from 1985-1988, residents of east Baltimore
- 40+ age
- 2400 BLACK, 2900 WHITE
- all received glaucoma testing: tonometry, VF, stereo disc photography
- first large-scale study to employ MODERN DIAGNOSTIC TECHNIQUES for glaucoma
Firs large scale study to employing modern diagnostic techniques for glaucoma
Baltimore eye survey
Baltimore eye study findings
- risk factors for glaucoma looked at-race, age, IOP, HTN, DM (not a risk factor), family Hx
- prevalence rates for POAG were 4-5X HIGHER IN BLACKS as compared with whites
Over the age of 80, blacks had 11% increase in POAG. It increases in whites but not nearly as much as in whites
Blacks had 2x prevalence of BLINDNESS AND VISUAL IMPAIRMENT than whites
Baltimore eye surgery and sex
No differences in sex
Blue mountains eye study
- CROSS SECTIONAL/COHORT STUDY of causes of age related vision loss conducted in 2 urban areas of Blue mountains region, near SYdney, Australia.
- WENT DOOR TO DOOR and gave eye exams
- 49-97
- 3600 participants
Blue mountains study and AMD/drusen
- smaller the drusen, the less severe it is (no Association with AMD) <63um
- RR 3 for those with drusen >63um (3x risk)
- > 125um
Soft drusen: none=no risk
Distinct soft RR 4.6
Indistinct or reticular is more risky
Location: <63um to 250um, higher risk of AMD
Closer to the fovea center=risk much higher (over 11%). As you get right close to the fovea, it actually drops a little some reason
Hyperpigmentation: no=no risk, no association, If present=RR 8x the risk
LA Latino Eye Study (LALES)
- POPULATION BASED ON CRESS SECTIONAL/COHORT STUDY
- lived in and around LA county
- average age 55
- 80% MEXICAN origina
- baseline exam phase 200-2003, follow ups 2004-2008
LALES outcomes
- primary: PREVALENCE of visual impairment, blindness, cataract, glaucoma, DR, AMD
- secondary: RISK FACTORS assocaited with eye disease, health related quality of life and vision related quality of life
Prevalence of types of DR among diabetics in LALES
As the patient has had diabetes longer, the prevelance of any type of DR climbs
-DM over 15 years, DR prevalence is almost 80% in Latinos
The long you have DM, the more likely you are to have DR
Mild NPDR and length of time with DM
Peaks at 5-9 years with DM, and then declines with duration of DM for some reason
Orinda study: school screening
- kids
- 1950s
Goal of the Orinda study
- the design the least expensive, least technical and most effective SCREENING PROGRAM for finding essentially all elementary school children with vision problems
- study WORKED BACKWARDS-did a comprehensive eye exam to identify chidlren who needed professional attention, then evaluated 6 SCREENING PROTOCOLS that would best pick them up
Most effective technique of the Orinda study
- MODIFIED CLINICAL TECHNIQUE (MCT)
- distance and near VA
- distance and near CT
- ret with lens rack
- direct ophthalmoscope
Referral for VA: Orinda
20/40 or worse
Ret cut off for referral: orinda
+1.50 or more
-0.50 or more myopia
+/-1.00 DC ore mor eastigmatism
+/-1.00 anisometropia
Distance CT referral: CT
Any tropia
5 EP
5XP
2 hyper
Near CT referral orinda
Any tropia
6 EP
10 XP
2 hyper
MCT results: orinda
96% sensitivity
98% specificity
Other important findings of Orinda
- incidence of vision problems increases at rate of 1.6%/year
- ages 5-7, 18% had vision problems
- ages 13-15, 31% had vision problems
Importance of Orinda study
- performed by INTERDISCIPLINARY TEAM; ODs, OMD, stats, school psychologists, parents, teachers
- those who had previous eye care more likely to be easily managed at follow up, even if they still failed the screening
- MCT most economical screening programs INCLUDING COST OF NEEDING OD, WHEN TAKING INTO ACCOUNT COSTS TO THE COMMUNITY FOR OVER REFERRALS
Criticisms of the orinda study
- generalizability
- MCT reliance on professionals
- not diverse
- limited evaluation of visual skills related to school performance
- other studies have replaced it. Vision in preschoolers (VIP) study. Designed to identify high refractive error, strab in younger kids
