Risk factors for hip fracture in men
 Low
BMD and RF for low BMD
 Previous
 Low
fractures
body mass
 Taller
 Frequent
falls and RF for falls
Risk factors for osteoporosis in men
Causes of secondary osteoporosis

Hypogonadism

Steroid therapy

Immobilization

Alcoholism

RA

Cancer

Thyrotoxicosis
Risk factors for osteoporosis in men

Aging

Thinness

Low calcium intake

Very low protein intake

Inactivity

Decreased androgen

Decreased estrogen
Design of cohort studies
Exposure
Outcomes
(death / disease
/ others)
Why do we need cohort studies?
 Cross-sectional
studies can only
describe associations
 Cohort
studies can
- Defined temporal relationship
- Study multiple outcomes
- Can be converted to RCCT
Determinants of validity of
cohort studies
 Sampling
method
 Sample
size
 Validity
of measurements
 Completeness
of follow up
What is known about determinants
of BMD and fractures?

Study of Osteoporotic fractures (SOF)

Dubbo study (Australia)

Rancho Bernando study

NHANES I, II, III

STORM
Correlates of femoral neck BMD
(Orwoll)
Factors
Age (5 years)
Weights (10 kg)
Fracture history
Hypertension
COAD
Gastrectomy
Current alcohol
Current smoking
% diff
-2.6
5.4
-7.4
4.2
-6.3
-11.6
4.9
-3.9
Sampling Method

Volunteer samples (independent walking)

Stratified by age group

65 - 69
33%
70 - 74
35%
≥ 75
31%
2000 men and 2000 women
Questionnaire for Mr & Ms Os

General including falls
(Stanford Health Assessment)

Cigarette smoking

Alcohol consumption
Questionnaire for Mr & Ms Os

Dietary intake (Block food frequency)

Medication use

Physical activity (PASE)

Mental status by MMSE

Depression by Geriatric Depression Scale
Physical examination for
Mr & Ms Os

Height and Weight

BMD by DEXA (Hologic QDR 4500W)

Ankle / arm BP index

Visual function : acuity, depth

Neuromuscular : grip strength, walk
speed, chair stand
Outcome measures
 Fractures
 BMD
 QCT
(History and X-Ray)
Characteristic of MrOs Subjects
(MeanSD)
Mean (SD)
Age
72.4 (5)
Height (cm)
163.1 (5.7)
Weight (kg)
62.4 (9.4)
BMI (kg/m2)
23.4 (3.1)
PASE score
97.3 (50.3)
PASE Scoring
Sitting Job + no exercise
33
Sitting Job +
Aerobic Exercise 3-4 times per week
96
Job that requires standing and walking +
No exercise
184
Job that requires standing and walking +
Aerobic Exercise 3-4 times per week
221
Characteristic of MrOs Subjects
(MeanSD)
Diet
Total calories intake (kcal)
Protein intake (g)
Calcium intake (mg)
Mean (SD)
2161 (747)
90 (41)
649 (344)
Characteristic of MrOs Subjects
Percentage
Current cigarette smoking
11.9%
Alcoholism - drink 4 /day in p12m
0.4%
- ever drink 5/day
8.0%
Had 1 or more fracture
13.7%
Diabetes mellitus
14.7%
Thyroid disease
2.1%
COPD
11.6%
Determinants of BMD in
Chinese men (Age-adjusted)

What are the physical
characteristics that are associated
with BMD in Chinese men?
Determinants of BMD in
Chinese men (Age-adjusted)

Percent
difference
Weight (5 kg):
+3.6
Determinants of BMD in
Chinese men (Age-adjusted)

What medical factors are
associated with BMD in Chinese
men?
Determinants of BMD in
Chinese men (Age-adjusted)

Medical Diseases associated with lower
BMD:
Percent
difference
– Chronic obstructive lung disease
5.8)
(-
– Gastrointestinal surgery
4.7)
(-
Determinants of BMD in
Chinese men (Age-adjusted)

Medical Diseases associated with
higher BMD:
Percent difference
– Hypertension
(4.0)
– Diabetes
(6.9)
– Hyperthyroidism
(5.1)
Determinants of BMD in
Chinese men (Age-adjusted)

Medications associated with lower
BMD:
difference
Percent
Inhaled corticosteroids (0.9%)
12.9)
Oral corticosteroids
4.4)
(0.6%)
Medications associated with hiher
((-
Determinants of BMD in
Chinese men (Age-adjusted)

What about lifestyle factors?
Determinants of BMD in
Chinese men (Age-adjusted)

Cigarette Smoking:
Percent difference
Current smokers
More than 46 packyrs
(-4.6)
(-3.1)
Determinants of BMD in
Chinese men (Age-adjusted)

Physical Activity:
Percent difference
– PASE
(0.5)
– Total number of city streets per day for
normal routine and exercises:
20 or above (25% of subjects) (1.8)
Determinants of BMD in
Chinese men (Age-adjusted)

Dietary Factors:
Percent difference

– Calcium (mg) per day (50mg)
(0.2)
– Protein (g) per day (10g)
(0.2)
Depression:
– GDS score (3)
(-1.4)
Multivariate model of risk factors
for total hip BMD (MrOs)
% Diff (95% CI)
Age (per 5 yr)
-0.7 (-1.3, -0.1)
Body weight (per 5 kg)
3.6 (3.3, 3.9)
Grip strength (per 5 kg)
0.8 (0.3, 1.3)
Multivariate model of risk factors
for total hip BMD (MrOs)
% Diff (95% CI)
COPD
-2.5 (-4.3, -0.8)
GI surgery
-2.8 (-4.6, -1.0)
Inhaled steroid
-8.3 (-14.3, -2.3)
Diabetes mellitus
4.0 (2.4, 5.6)
Thyroid disease
4.1 (0.2, 7.9)
Multivariate model of risk factors
for total hip BMD (MrOs)
% Diff (95% CI)
Current smoker
-1.5 (-3.2, 0.2)
Thiazide diuretic
2.7 (-0.3, 5.6)
Calcium intake (per 50 mg)
0.1 (-0.01, 0.2)