2004 OPEN FORUM Abstracts
Smoking and Bone Density in Men: Results from a National Survey
Michael
E. Anders, M.P.H., RRT,* Lori W. Turner, Ph.D, RD,†
and Horace Spencer, M.S.* *University of Arkansas for Medical
Sciences, Little Rock, Arkansas University
of Arkansas, Fayetteville, Arkansas
Background.
Osteoporosis is an insidious, chronic disease that precipitates
debilitating, costly, and sometimes lethal fractures. One-eighth of
men will suffer osteoporotic fractures in their lifetime. Though men
have a lower incidence of hip fractures than women, they are twice as
likely to die in the year afterward. National selection criteria for
osteoporosis screening with bone density measurement for women rely
on identification of major risk factors, including smoking, but
selection criteria for men are lacking. The purpose of this study
was to determine correlates of bone density in men.
Methods. Sample: The Centers for Disease Control collected data from
a nationally representative sample via a stratified, multistage
probability design. The study extracted data using inclusion
criteria of males, ages 20 through 90 years, for who bone density
data were available. The study excluded those who were
institutionalized and minorities. Testing instrument: The
testing instrument was the National Health and Nutrition Examination
and Survey III. Dual energy x-ray absorptiometry measured bone
density. The Mayo Clinic reviewed each test. Random test-retest
demonstrated reliability. Statistical analysis: The study
employed statistical software, SPSS™, to compute all
statistical tests. Univariate linear regression tested each of the
following as correlates of bone density: age, weight, smoking
pack-years, physical activity, chronic disease, weight loss, calcium
intake, alcohol intake, serum retinyl esters, and serum vitamins C
and E. Each independent variable with a p value < 0.25 in
the univariate analysis was then retested for significance in a
full-model multivariable linear regression and subsequently in a
reduced-model multivariable linear regression at an alpha = .01.
Covariates in the reduced-model were tested for both collinearity and
two-way interactions.
Results.
The study sample included 2,930
subjects, with a mean age = 54.87 (+ 19.61) years and a mean
weight = 81.49 (+ 15.18) kg.
Bone
Density: Reduced Multivariable Model
| Standardized β | p value | |
| Age | (-) .630 | < .001 |
| Weight | .299 | < .001 |
| Age x weight | .352 | < .001 |
| Physical activity | .074 | < .001 |
| Smoking pack-years | (-) .060 | < .001 |
| Vitamin C | .057 | < .001 |
Conclusion.
Our study results provided sufficient evidence to suggest that
in men: (a) weight, physical activity, and Vitamin C were associated
with increased bone density; and (b) age and smoking pack-years were
associated with decreased bone density. Interaction existed between
age and weight; however the slopes resulting from regression models
of bone density as functions of quartiles of age and weight were
similar.