Measurements from the Alpha Omega Cohort
At baseline (2002-2006), patients were examined by trained research nurses, either at home or in the hospital. The nurses measured height, body weight, waist circumference and blood pressure. Blood samples were taken. Self-administered questionnaires were used to collect data on disease history, current health, medication use, dietary pattern, physical activity, smoking pattern and alcohol consumption.
Interviews and blood samples
We have a collection of blood samples that have been analyzed for the measurement of glucose, total cholesterol, HDL cholesterol, triglycerides and the fatty acid composition of cholesteryl esters. In addition to that, we have the processed annual telephone interviews that were done to collect data on health status and medication use.
Follow-up for morbidity and mortality
Follow-up for vital status and cause-specific mortality is ongoing. Data are obtained from the Dutch National Mortality Registry (Statistics Netherlands). One patient was lost to follow-up and censored after 2.9 y.
Fatal events were coded according to the International Classification of Diseases, 10th Revision, combining primary and secondary causes of death. CVD mortality included IHD (codes I20–I25), cardiac arrest (I46), heart failure (I50), stroke (I60–I69), and sudden death, undefined (R96). IHD mortality included codes I20–I25, I46, and R96.
The benefits of a large-scale trial:
The primary purpose of large-scale trials is to test hypotheses without the potential confounding that so often limits the interpretation of results of observational prospective cohort studies. Moreover, the data from large-scale trials can also be used for observational research. In the Alpha Omega Trial the patients were included between May 2002 and December 2006. The data can be used to study trends in cardiovascular risk management and risk factors at the population level. It is also possible to study cross-sectional and prospective associations of diet and lifestyle with risk factors, biomarkers and indicators of health.
Data collection
Download our questionnaires and data dictionaries, or find the tables below for an overview of our measurements.
Questionnaires (in Dutch)
Data dictionaries
| Measurements | Variable |
|---|---|
| Demographics | Sex |
| Age | |
| Marital status | |
| Socioeconomic status | Educational level |
| Adherence to the protocol | Treatment group |
| Compliance | |
| Margarine use |
| Measurements | Variable |
|---|---|
| Smoking | |
| Alcohol use | |
| Physical activity | Physical Activity (PASE) |
| General health | Self-rated health |
| Weight loss and gain | |
| Kidney function (eGFR) | |
| Prescribed diet | |
| History of: | Hypertension |
| Stroke | |
| Aneurysm | |
| Diabetes | |
| Cancer | |
| Family history of: | Myocardial infarction |
| Diabetes | |
| Medication use | Coded according to ATC classification index 2009 |
| Supplements | Vitamin pills and food supplements |
| Questions for female subjects | Age at menarche and menopause |
| Former use of oral contraception | |
| Physical examination | Weight, height, waist |
| Blood pressure and heart rate |
Baseline n=4837
20m follow-up n=810
40m follow-up n=4278
| Measurements | Variable | Time point | N |
|---|---|---|---|
| Cognitive functioning | MMSE (Mini-Mental State Examination) | Baseline 20m follow-up 40m follow-up | 4837 810 2530 |
| Depression / optimism | Depressive symptoms (GDS-15) | Baseline 20m follow-up 40m follow-up | 791 809 4155 |
| Dispositional optimism (LOT-R and 4Q) | Baseline 20m follow-up 40m follow-up | 791 809 4155 |
Blood collection
| Variable | Time point | N | |
|---|---|---|---|
| Serum, plasma | Baseline 20m follow-up 40m follow-up | 4785 810 2503 | |
| Red blood cells | Baseline 40m follow-up | 3956 97 | |
| DNA | Whole genome genotyping | Baseline | 4785 |
| Date and time blood collection | Hours fasting |
Blood parameters
| Variable | Time point | N | |
|---|---|---|---|
| Serum lipids | Total cholesterol | Baseline 20m follow-up 40m follow-up | 4837 810 2530 |
| HDL cholesterol | |||
| LDL cholesterol | |||
| Triglycerides | |||
| Glucose | Baseline 20m follow-up 40m follow-up | 4837 810 2530 | |
| Plasma fatty acid profiles | Baseline 20m follow-up 40m follow-up | 4746 795 1267 | |
| Biomarkers | PSA | Baseline 20m follow-up 40m follow-up | 1622 – 1622 |
| Testosterone | Baseline 20m follow-up 40m follow-up | 1900 – 1900 | |
| pro-BNP | Baseline 20m follow-up 40m follow-up | 1375 – 643 | |
| Creatinine, CRP, Cystatin-C | Baseline 20m follow-up 40m follow-up | 4650 – 2468 | |
| FGF-23, Phosphate | Baseline 20m follow-up 40m follow-up | 490 – 490 |
| Measurements | Variable |
|---|---|
| 203-item FFQ | Foods |
| Nutrients | |
| Bioactives | |
| Diet scores |
Baseline n=4384
20m follow-up n=738
40m follow-up n=2233
| Measurements | Variable | |
|---|---|---|
| Fatal events Continuous follow-up | Cause of death | ICD-10 |
| Non-fatal events 40 m follow-up | MI | |
| Stroke | ||
| Cardiac arrest | ||
| Cardiac interventions | PCI | |
| CABG | ||
| ICD placement | ||
| Diabetes |