0

The full content of Annals is available to subscribers

Subscribe/Learn More  >
Articles |

Genetic and Environmental Influences on Total-Body and Central Abdominal Fat: The Effect of Physical Activity in Female Twins

Katherine Samaras, MBBS, FRACP; Paul J. Kelly, MD, FRACP; Mathias N. Chiano, PhD; Tim D. Spector, MD, MSc, FRCP; and Lesley V. Campbell, MBBS, FRCP, FRACP
[+] Article and Author Information

From St. Thomas' Hospital, London, and Gemini Holdings plc, Cambridge, United Kingdom; and St. Vincent's Hospital and St. Vincent's Clinic, Darlinghurst, New South Wales, Australia.


Ann Intern Med. 1999;130(11):873-882. doi:10.7326/0003-4819-130-11-199906010-00002
Text Size: A A A

Background: The increasing prevalence of obesity has focused attention on the contribution of physical activity and its interaction with predisposing genetic factors.

Objective: To examine 1) the relation between physical activity and total-body and central abdominal fat, independent of genetic and other environmental factors, and 2) the influence of physical activity in persons who are genetically susceptible to generalized or central adiposity.

Design: Cross-sectional study.

Setting: A London academic teaching hospital.

Patients: 970 healthy female twins (mean age, 55.5 years [range, 39 to 70 years]; body mass index, 24.4 kg/m2 [range, 16.4 to 44.0 kg/mg 2]). There were 241 monozygotic pairs, 228 dizygotic pairs, and 32 women whose co-twin lacked complete data. Fifty-six percent of participants were of normal weight, 30% were overweight, 7% were obese, and 7% were underweight.

Measurements: Total-body and central abdominal fat were measured by dual-energy x-ray absorptiometry. Physical activity was assessed by quantitative and semi-quantitative questionnaires. Data on dietary intake, socioeconomic status, smoking status, and use of hormone replacement therapy (HRT) were also gathered.

Results: Total-body and abdominal central adiposity were lower with higher levels of home, sporting, and sweating-associated activity. Total-body and central abdominal fat were 5.6 kg and 0.44 kg lower, respectively, in participants who reported vigorous weight-bearing activity. Physical activity was the strongest independent predictor of total-body fat (β = −0.6 [CI, −1.06 to −0.15]; P = 0.009) and central abdominal fat (β = −0.07 [CI, −0.1 to −0.03]; P < 0.001) in a regression model that included age, diet, smoking, HRT use, and socioeconomic status. Monozygotic twin pairs who were concordant for smoking and HRT status but were discordant for moderate-intensity sport showed greater within-pair differences in total-body fat than those who were concordant for activity level. In this model, 1 and 2 hours of moderate-intensity sport accounted for within-pair differences of 1.0 kg (P = 0.050) and 1.4 kg (P = 0.040), respectively, of total-body fat. In participants who had an overweight twin, higher levels of physical activity were still associated with 3.96-kg lower total-body fat and 0.53-kg lower central abdominal fat.

Conclusions: Current physical activity predicts lower total-body and central abdominal adiposity in healthy middle-aged women. After controlling for genetic and environmental factors, the influence of physical activity was greater than that of other measured environmental factors. Participants with a genetic predisposition to adiposity did not show a lesser effect of physical activity on body fat mass.

Figures

Grahic Jump Location
Figure 1.
Within-pair differences in total-body fat in 156 monozygotic twin pairs who were concordant (white bars) or discordant (striped bars) for sporting activity.P

* ≤ 0.05. Error bars represent upper bound of SE.

Grahic Jump Location
Grahic Jump Location
Figure 2.
The influence of genetic risk and physical activity level on total-body fat mass (top) and central abdominal fat mass (bottom) in middle-aged female twins.

White bars represent low physical activity; striped bars represent high physical activity. Error bars represent upper bound of SE.

Grahic Jump Location

Tables

References

Letters

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Comments

Submit a Comment
Submit a Comment

Summary for Patients

Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.

Toolkit

Buy Now

to gain full access to the content and tools.

Want to Subscribe?

Learn more about subscription options

Advertisement
Related Articles
Related Point of Care
Topic Collections
PubMed Articles
Forgot your password?
Enter your username and email address. We'll send you a reminder to the email address on record.
(Required)
(Required)