Table. Baseline and Change Point Characteristics by Age-Decade of Hypertension Onset.
| Characteristics | Age at Hypertension Onset | P Value | ||||
|---|---|---|---|---|---|---|
| 40-49 Years | 50-59 Years | 60-69 Years | 70-79 Years | No Onset | ||
| Baseline characteristica | ||||||
| No. | 218 | 228 | 240 | 130 | 436 | |
| Age at enrollment, mean (SD), y | 35.2 (2.5) | 35.5 (2.7) | 34.7 (2.6) | 35.4 (2.7) | 35.5 (2.7) | .004 |
| Women, No. (%) | 134 (61.5) | 155 (68.0) | 163 (67.9) | 78 (60.0) | 260 (59.6) | .22 |
| BMI, mean (SD) | 24.4 (3.8) | 23.9 (3.5) | 23.3 (3.2) | 23.6 (3.1) | 23.6 (3.1) | .01 |
| Current smoker, No. (%)b | 142 (67) | 135 (63) | 137 (60) | 77 (63) | 304 (74) | .52 |
| Serum cholesterol (total), mean (SD), mg/dLc | 211 (41) | 207 (37) | 202 (36) | 203 (39) | 205 (37) | .12 |
| Systolic BP, mean (SD), mm Hg | 124 (8) | 122 (8) | 119 (9) | 117 (9) | 118 (10) | <.001 |
| Diastolic BP, mean (SD), mm Hg | 79 (6) | 77 (6) | 76 (7) | 75 (7) | 75 (7) | <.001 |
| Change point characteristic, estimate (95% CI)d | ||||||
| Age at change point, y | 39.0 (37.9 to 40.0) |
43.8 (42.5 to 45.0) |
56.2 (55.0 to 57.5) |
61.0 (59.7 to 62.2) |
NA | <.001 |
| Systolic BP at change point, mm Hg | 123.2 (122.7 to 130.1) |
122.0 (120.3 to 123.9) |
124.9 (120.2 to 127.9) |
120.5 (118.0 to 123.2) |
NA | .29 |
| Slope before change point, mm Hg/y | 0.02 (−0.43 to 0.40) |
0.20 (0.02 to 0.39) |
0.43 (0.36 to 0.48) |
0.25 (0.18 to 0.31) |
NA | <.001 |
| Slope after change point, mm Hg/y | 1.87 (1.62 to 2.09) |
1.41 (1.27 to 1.54) |
1.50 (1.30 to 1.62) |
1.53 (1.30 to 1.62) |
NA | .01 |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); BP, blood pressure; NA, not applicable.
SI conversion factor: To convert cholesterol to mmol/L, multiply by 0.0259.
Baseline characteristics between groups were compared using 1-way analysis of variance for continuous variables and χ2 tests for categorical variables.
Data are missing for 71 individuals.
Data are missing for 40 individuals.
Change point estimates were derived using the mixed segmented model. Empirical confidence limits were derived from bootstrapping. Percentile limits are reported to accommodate for potentially non-normal sampling distributions of parameter estimates. We used the Cochran Q test to assess heterogeneity in the change point characteristics.