Table 1.

OH variants and their link to dementia

OH variant	Description	Link to incident dementia
Classic	Sustained ↓ SBP of ≥20 mmHg or ↓ DBP of ≥10 mmHg up to 3 mins after transition to upright posture (↓ SBP of ≥30 mmHg or ↓ DBP of ≥15 mmHg, if hypertensive)	General population: ~21% increased risk of dementia45 α-Synucleinopathy: 3- to 7-fold increased risk of dementia in patients52,54
IOH	↓ SBP of ≥40 mmHg or ↓ DBP of ≥20 mmHg within 15 s of transition to upright posture but fully restored by 30 s	Insufficient evidence to exclude an association More common in younger adults Not considered pathological, in general
OH-30	↓ SBP of ≥20 mmHg or ↓ DBP of ≥10 mmHg not recovered by 30 s but fully restored by 3 mins after transition to upright posture (often coincides with IOH)	2.8-fold increased risk of conversion from MCI to dementia47
DOH	Initial recovery, but sustained ↓ SBP of ≥20 mmHg or ↓ DBP of ≥10 mmHg beginning >3 mins after transition to upright posture	A marker of early/mild OH Linked to incident α-synucleinopathy23

Note: ↓, decrease.

Abbreviations: DBP, diastolic blood pressure; DOH, delayed-onset OH; IOH, initial OH; MCI, mild cognitive impairment; OH-30, delayed-recovery OH; OH, orthostatic hypotension; SBP, systolic blood pressure.