Elsevier

Preventive Medicine

Volume 45, Issue 6, December 2007, Pages 436-441
Preventive Medicine

Eight-year change in body mass index and subsequent risk of cardiovascular disease among healthy non-smoking men

https://doi.org/10.1016/j.ypmed.2007.06.022Get rights and content

Abstract

Objective.

To determine how change in BMI over 8 years is associated with risk of subsequent cardiovascular disease (CVD) among middle aged men.

Methods.

Prospective cohort study among 13,230 healthy men (aged 51.6 ± 8.7 years) in the Physicians' Health Study. BMI was collected at baseline in 1982 and after 8 years, at which time follow-up began. Subsequent CVD events were collected and confirmed through March 31, 2005. Cox proportional hazards models evaluated BMI at 8 years and risk of CVD, 8-year change in BMI and risk of CVD, and whether change in BMI added prognostic information after the consideration of BMI at 8 years.

Results.

1308 major CVD events occurred over 13.5 years. A higher BMI at year 8 was associated with an increased risk of CVD. Compared to a stable BMI (± 0.5 kg/m2), a 0.5–2.0 kg/m2 increase had a multivariable-adjusted RR of 1.00 (0.86–1.16). A ≥ 2.0 kg/m2 increase had a multivariable-adjusted RR of 1.39 (1.16–1.68), however further adjustment for BMI reduced the RR to 1.00 (0.81–1.23). A decrease in BMI had a multivariable RR of 1.23 (1.07–1.42) which was unaffected by adjustment for BMI at 8 years.

Conclusion.

A higher BMI and a rising BMI were both associated with an increased risk of CVD, however an increasing BMI did not add prognostic information once current BMI was considered. In contrast, a declining BMI was associated with an increased risk of CVD independent of current BMI.

Introduction

As rates of overweight and obesity continue to increase in the United States (Ogden et al., 2006) and worldwide (Joint WHO/FAO Expert Consultation, 2003), the burden of disease from excess weight is becoming substantial (Allison et al., 1999) and may soon reduce life expectancy (Olshansky et al., 2005, Ezzati et al., 2002). While obesity has been consistently associated with an increased risk of cardiovascular disease (CVD) (Mcgee, 2004, Joint WHO/FAO Expert Consultation, 2003), few studies have evaluated whether the consideration of long-term change in BMI may provide additional information in the prediction of CVD.

Prior observational studies have supported the idea that the lowest risk of CVD may be among those with a stable weight (Harris et al., 1997, Diaz et al., 2005, Wannamethee et al., 2005) while both weight loss and gain have been associated with a poorer health status (Harris et al., 1997) and increased CVD mortality (Breeze et al., 2005, Lee and Paffenbarger, 1993). In assessing change in BMI, observational studies must be careful to minimize confounding by factors such as smoking status, physical activity (Rosengren et al., 1999), and potential underlying malignancy (Wannamethee et al., 2002).

The objective of this study was to use prospective data from a large cohort with long-term follow-up to better understand how change in BMI is associated with risk of CVD and whether the consideration of BMI trajectory could add prognostic information beyond knowledge of current BMI. Therefore, we evaluated how change in BMI over the prior 8 years was associated with risk of major CVD events among 13,230 healthy men followed for a median of 13.5 years.

Section snippets

Study population

Study subjects are from the Physicians' Health Study (PHS). In 1982–3, letters were sent to 261,248 U.S. male physicians aged 40 to 84 years on the American Medical Association mailing list that included an invitation to participate in a randomized, double-blind, placebo-controlled trial testing aspirin and beta-carotene in the primary prevention of CVD and cancer. The letters contained informed consent forms and an initial questionnaire to provide baseline information. By the end of 1983,

Results

The study cohort of 13,230 participants had a baseline mean (SD) age of 51.6 (8.7) years and average BMI of 24.6 (2.7) kg/m2 (Table 1). Based upon WHO criteria, 60% were in the normal weight category while 36% were overweight and 4% were obese. Among these male physicians, 42% were former smokers, 15% drank alcohol at least daily, and 57% exercised at least twice a week. A history of hypertension was reported by 19%, and the average SBP was 124.6 (11.1) mm Hg.

At return of the 8-year

Discussion

In this large prospective study of healthy men, a BMI increase of ≥ 2.0 kg/m2 over the prior 8 years was associated with an increased risk of CVD, however this did not add prognostic information when current BMI was considered. A decline in BMI of more than 0.5 kg/m2 was associated with an increased risk of CVD regardless of current BMI, particularly among older men. The consideration of a long-term decrease in BMI may be useful in assessing risk of subsequent CVD.

The characteristics of our

Conclusions

In this prospective cohort study of healthy middle-aged non-smoking men, higher levels of baseline BMI were associated with an increased risk of CVD and knowledge of an increasing BMI over the prior 8 years did not improve the ability to predict risk of CVD. Men with a decline of more than 0.5 kg/m2 were at an increased risk of CVD independent of current BMI, and the consideration of a long-term decline in BMI may be useful in evaluating risk of CVD, particularly among older men.

Acknowledgments

This work was supported by grants CA-34944, CA-40360, HL-26490 and HL-34595 from the National Institutes of Health.

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  • Cited by (0)

    This work was presented as an abstract on June 12, 2006 at the International Society of Atherosclerosis meeting in Rome, Italy.

    1

    Dr. Bowman is supported by a Career Development Award from the Veterans Affairs Cooperative Studies Program. This work was supported by grants CA-34944, CA-40360, HL-26490 and HL-34595 from the National Institutes of Health.

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