Table 4.
Cardiovascular risk factor levels according to level of education in the cohort and within sibships stratified by age-difference in sibships of only two siblings
| Sibling age-difference | Education | Cohort | Within sibships | Difference | Cohort | Within sibships | Difference | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Years | Level | βCohort (95% CI) | βWithin sibships (95% CI) | βΔ (95% CI) | % | p | βCohort (95% CI) | βWithin sibships (95% CI) | βΔ (95% CI) | % | p |
| Per one lower level | Systolic blood pressure (mmHg) | Diastolic blood pressure (mmHg) | |||||||||
| 0-1 | 0.79 (0.40, 1.18) | 0.35 (-0.27, 0.97) | 0.44 (-0.04, 0.92) | -56 | <0.001 | 0.29 (-0.00, 0.56) | -0.07 (-0.51, 0.37) | 0.35 (0.01, 0.69) | -126 | <0.001 | |
| >1-6 | 1.00 (0.93, 1.07) | 0.72 (0.60, 0.83) | 0.28 (0.19, 0.37) | -28 | <0.001 | 0.62 (0.56, 0.67) | 0.44 (0.36, 0.52) | 0.18 (0.11, 0.24) | -29 | <0.001 | |
| >6 | 1.11 (0.95, 1.28) | 0.95 (0.70, 1.21) | 0.16 (-0.03, 0.36) | -14 | <0.001 | 0.64 (0.53, 0.76) | 0.54 (0.36. 0.72) | 0.10 (-0.04, 0.24) | -16 | <0.001 | |
| Total cholesterol, (mmol/l) | Heart rate (beats/min) | ||||||||||
| 0-1 | 0.07 (0.04, 1.00) | 0.01 (-0.03, 0.06) | 0.06 (0.03, 0.09) | -81 | <0.001 | 1.28 (0.92, 1.65) | 0.76 (0.16, 1.37) | 0.52 (0.04, 1.00) | -41 | 0.300 | |
| >1-6 | 0.10 (0.10, 0.11) | 0.07 (0.06, 0.08) | 0.03 (0.03, 0.04) | -31 | <0.001 | 1.38 (1.31, 1.44) | 1.12 (1.01, 1.22) | 0.26 (0.18, 0.35) | -19 | <0.001 | |
| >6 | 0.10 (0.09, 0.11) | 0.07 (0.05, 0.09) | 0.03 (0.02, 0.05) | -32 | <0.001 | 1.32 (1.17, 1.47) | 1.01 (0.77, 1.25) | 0.32 (0.13, 0.50) | -24 | 0.004 | |
| Body mass index, (kg/m2 | Height (cm) | ||||||||||
| 0-1 | 0.19 (0.09, 0.30) | 0.02 (-0.14, 0.17) | 0.18 (0.06, 0.30) | -91 | 0.033 | -0.49 (-0.66, -0.33) | -0.12 (-0.34, 0.10) | -0.37 (-0.53, -0.22) | 75 | <0.001 | |
| >1-6 | 0.29 (0.27, 0.31) | 0.17 (0.14, 0.20) | 0.12 (0.10, 0.14) | -42 | <0.001 | -0.49 (-0.52, -0.46) | -0.23 (-0.27, -0.18) | -0.26 (-0.29, -0.24) | 54 | <0.001 | |
| >6 | 0.30 (0.26, 0.35) | 0.18 (0.11, 0.24) | 0.13 (0.08, 0.18) | -42 | <0.001 | -0.46 (-0.53, -0.39) | -0.23 (-0.32, -0.14) | -0.23 (-0.29, -0.17) | 50 | <0.001 | |
| Smoking status and pack years (category) | SCORE (percentage points) | ||||||||||
| 0-1 | 0.29 (0.25, 0.34) | 0.18 (0.11, 0.24) | 0.12 (0.06, 0.17) | -39 | <0.001 | 0.061 (0.048, 0.074) | 0.020 (-0.025, 0.042) | 0.041 (0.024, 0.059) | -68 | <0.001 | |
| >1-6 | 0.32 (0.32, 0.33) | 0.23 (0.22, 0.24) | 0.09 (0.08, 0.10) | -29 | <0.001 | 0.065 (0.063, 0.068) | 0.046 (0.043, 0.050) | 0.019 (0.016, 0.022) | -29 | <0.001 | |
| >6 | 0.30 (0.29, 0.32) | 0.23 (0.21, 0.26) | 0.07 (0.05, 0.09) | -23 | <0.001 | 0.067 (0.061, 0.072) | 0.054 (0.045, 0.063) | 0.013 (0.006, 0.020) | -19 | 0.001 | |
Number of individuals and number of sibships in sibships of only two siblings: 145,976 individuals in 72,988 sibships. Number of individuals and number of sibships stratified by difference in birth year: 4,208 individuals in 2,104 sibships for 0–1 years age-difference (of whom 2,540 individuals were born in the same year and month), 118,346 individuals in 59,173 sibships for >1–6 years age-difference, and 23,422 individuals in 11,711 sibships for >6 years age-difference. β is the beta regression coefficient. 95% CI is 95% confidence interval. βΔ = βCohort – βWithin sibships. % = ((βCohort – βWithin sibships) / βCohort)*100. P is Hausman specification test p for difference between cohort and within sibships effect estimates. Educational levels 1–5: (1) up to 7–9 years; (2) 10–11 years; (3) 12 years (4) 13–16 years; (5) >16 years. Smoking status and pack years categories 1-5: (1) never smoker, (2) past smoker and <20 pack-years, (3) past smoker and >20 pack-years, (4) current smoker and <20 pack-years, (5) current smoker and >20 pack-years). SCORE is the Systematic COronary Risk Evaluation risk prediction score of 10-year cardiovascular mortality. All analyses are adjusted for age at examination and examination year, both centred on median, and for sex. Analyses of blood pressure are adjusted for current antihypertensive treatment