Fig. 2
From: The association between carbon and nitrogen stable isotope ratios of human hair and hypertension
Relation of δ13C and δ15N values to the Korean Society of Hypertension classification of blood pressure in 313 subjects without antihypertensive medication. A δ13C. B δ15N. The scatter plots are shown with regression lines (black solid lines) and 95% confidence intervals (gray areas). Normal blood pressure (BP), systolic BP (SBP) < 120 mmHg and diastolic BP (DBP) < 80 mmHg; elevated BP, SBP 120–129 mmHg and DBP < 80 mmHg; prehypertension, SBP 130–139 mmHg or DBP 80–89 mmHg; hypertension grade 1 (HTN 1), SBP 140–159 mmHg or DBP 90–99 mmHg; hypertension grade 2 (HTN 2), SBP ≥160 mmHg or DBP ≥100 mmHg. PDB, Pee Dee Belemnite