By utilizing Near infrared spectroscopy (NIRS), the local blood flow, tissue oxygenation (StO2), and recovery time of ischemic leg; can be determined. It is reasonable to standardize an easy, simple and safe Active Pedal Plantarflexion (APP) exercise test working load which can achieve the lowest StO2 and other parameters in ischemic leg through observation of NIRS. After standardized of an effective APP test, a determination of a new cutoff value of resting ABI in diagnosing PAD can probably be searched. Analysing the correlation of baPWV with ABI, atherosclerosis risk factors and parameters with atherosclerosis outcome. Observation the Sequential changes of baPWV, ABI and microalbuminuria after managing the atherosclerosis risks, and analyze their influence on the outcome of PAD, coronary artery disease(CAD) and cerebral vascular disease(CVA) outcomes.

Exercise testing by Active Pedal Plantar flexion:

The investigators plan to collect 140 cases:

1. Healthy subjects with no apparent atherosclerotic risk [< 65 y/o, no diabetic mellitus (DM), no hypertension, or no hyperlipidemia, not obese, not current smoker, no smoking history >10 years] 4(n=5)
2. Patients at risks (e.g. hypertension, hyperlipidemia) (n=5) but without DM,
3. Type 1 and Type 2 DM patients with normal ABI( >1.0)and normal Toe-brachial index (TBI) (> 0.6) without intermittent claudication(by Edinburgh claudication questionnaire), nor PAD diagnosis (n= 10)
4. DM normal ABI>1.0 and normal TBI (> 0.6) with suspected symptoms (intermittent claudication, non healing ulcer) (n=10),
5. DM normal or borderline ABI( >1, 0.91~0.99) but low TBI (< 0.6), or with suspected symptoms (intermittent claudication, non healing ulcer) (n=20),
6. DM patients with borderline ABI (0.91-0.99) (n=50) with or without leg symptoms,
7. DM patients abnormal Low ABI (<0.9) (n=30) with or without leg symptoms,
8. DM patients abnormal high ABI (> 1.3) (n=10)with or without leg symptoms, Post-exercise ABI with APP, and NIRS examination during APP exercise test will be performed.

The investigators also plan to collect 500 cases of nonpregnant, ≥ 40 years old DM patients, obtained baPWV and the resting ABI by oscillometric device (Omron colin, Japan). The investigators will apply this novel technique to assess the extent of arteriosclerosis and atherosclerosis by oscillometric device in our DM patient without PAD (ABI >0.9).

Collect baseline characteristics and follow up annual data: Age, sex, body weight, height, BMI, waist circumferences, history of smoking (ex-smoker, current), coexisting hypertension, hyperlipidemia, DM duration, presence of chronic DM complications of neuropathy, retinopathy (by fundus camera), nephropathy (cr, estimate glomerular filtration rate(eGFR), proteinuria, microalbuminuria). The biochemistry data involving atherosclerotic risk including: systolic blood pressure, diastolic pressure, mean pulse pressure, HbA1c, total cholesterol, LDL-Cholesterol(LDL-C), HDL-Cholesterol(HDL-C), triglyceride, creatinine, microalbuminuria,, high sensitive C-Reactive Protein (hs CRP), baseline EKG all will be collected. All the above data will be followed up annually for 3 years to analyze the correlation of progressive change of baPWV, ABI and microalbuminuria with the atherosclerosis event and mortality.

Inclusion Criteria:

• type 1 diabetic patients
• type 2 diabetic patients

Exclusion Criteria:

• Pregnancy
• Critical limb ischemia (gangrene change)
• A permanent pacemaker implant
• Systolic BP ≥ 200 mmHg or diastolic BP ≥100 mmHg
• Symptomatic orthostatic blood pressure drop ≥ 20 mmHg
• Severe critical aortic stenosis
• Acute medical illness, fever, systemic infection
• Uncontrolled atrial or ventricular dysrhythmias
• Uncontrolled sinus tachycardia≥ 120/min
• Peripheral venous insufficiency, thrombosis or thrombophlebitis
• Those who has factors known to influence the PWV
• The brachial-ankle PWV could not be measured on the right and left sides
• Orthopedic condition (ankle or foot) that cannot perform an active pedal plantar flexion (APP) technique (arthritis, hemiparesis, balance impairment etc.)

Nonpregnant & ≥ 20 years old type1 and type 2 diabetic patients