American Heart Association’s Life’s Simple 7 and incidence of venous thromboembolism

To the Editor

The American Heart Association (AHA) has recently promoted primary prevention of cardiovascular disease (CVD) by recommending that Americans optimize “Life’s Simple 7.” As described in Supplemental Table 1, Life’s Simple 7 comprises seven CVD risk factors or behaviors (smoking, body mass index, physical activity, diet, total cholesterol, blood pressure, and fasting serum glucose), which AHA categorized into ideal, intermediate or poor levels [1]. The Atherosclerosis Risk in Communities (ARIC) Study reported that the number of ideal levels achieved is associated strongly and inversely with subsequent incidence of arterial CVD and cancer [2, 3]. Although some of Life’s Simple 7 components (e.g., high BMI) are known to increase the risk of venous thromboembolism (VTE), only one previous study has suggested that greater adherence to Life’s simple 7 can reduce VTE [4]. We sought to verify whether Life’s Simple 7 relates to VTE (venous thrombosis and pulmonary embolism) incidence.

The ARIC Study [5] enrolled 15,792 men and women aged 45 to 64 years in 1987–1989, and conducted four subsequent examinations and annual telephone contact. For this analysis, we excluded those who were: not white or African American (n=48), had a prior VTE (n=276), were taking anticoagulants (n=73), were not fasting for 8 hours (n=503), had missing dietary data or had implausible energy intake (n=336), or had incomplete information on other Life’s Simple 7 components (n=458), which left 14,098 participants (n=10,617 whites and 3,481 African Americans).

At baseline, ARIC measured risk factors within its cohort and classified each risk factor according to AHA’s Simple 7 categories of ideal, intermediate, or poor (Supplemental Table 1) [1, 2]. For analysis, we further categorized adherence with Life’s Simple 7 in two ways. Firstly, we simply counted the number of ideal Life’s Simple 7 components that each participant met. Secondly, as done previously [5], we created a score in which each component was given points of 0, 1, or 2 to represent poor, intermediate, or ideal health categories, respectively, and these were summed to yield a Life’s Simple 7 score. This score was categorized as inadequate (0–4), average (5–9), or optimal (10–14) for cardiovascular health.

ARIC contacted participants annually by phone and asked about all hospitalizations in the previous year. To validate the VTE events, two physicians (ARF, MC) reviewed the hospital records using standardized criteria [6]. A diagnosis of deep vein thrombosis or pulmonary embolus required positive imaging tests. For this analysis, we restricted deep vein thromboses to those occurring in the lower extremity or vena cava.

Among the 14,098 ARIC participants aged 45–64, who were followed a median of 22.5 years, 629 incident VTEs were identified. As shown in Table 1, ARIC participants having ≥4 ideal components of Life’s Simple 7 at baseline had approximately half the VTE incidence of those with fewer ideal health components. As shown in Figure 1, the Life’s Simple 7 score (range 0–14, giving 2 points for ideal, 1 point for intermediate, and 0 points for poor components) was likewise associated inversely with VTE incidence. The age, sex, and race adjusted hazard ratios (95% CI) of VTE were: 1.0 (reference) for a Life’s Simple 7 score of 0–4 (inadequate), 0.77 (0.59, 1.01) for a score of 5–9 (average), and 0.44 (0.32, 0.61) for a score of 10–14 (optimal). Better BMI, physical activity, and blood pressure components individually contributed the most to the reduced VTE risk associated with Life’s Simple 7 adherence.

Table 1.

Incidence of Venous Thromboembolism (VTE) in Relation to the Number of Ideal AHA Life’s Simple 7 Components, ARIC, 1987–2011

# of ideal Simple 7 componentsa	Participants at Risk (N)	VTE events (N)	Person-years	VTE Incidence Rateb (95% CI)	Hazard Ratioc (95% CI)
0	384	19	6,460	2.94 (1.88, 4.61)	1 (Ref)
1	2,186	111	40,363	2.75 (2.28, 3.31)
2	3,639	196	70,476	2.78 (2.42, 3.20)	1.00 (0.80, 1.25)
3	3,719	182	75,173	2.42 (2.09, 2.80)	0.91 (0.73, 1.14)
4	2,518	85	52,543	1.62 (1.31, 2.00)	0.65 (0.49, 0.86)
5	1,260	26	27,348	0.95 (0.65, 1.40)	0.41 (0.27, 0.63)
6	375	10	8,149	1.23 (0.66, 2.28)	0.54 (0.29, 1.04)
7	17	0	377	0	--

^aIdeal Life’s Simple 7 components include nonsmoking, body mass index <25 kg/m², ideal physical activity, ideal diet score, serum cholesterol <200 mg/dL without medication, blood pressure <120/<80 mmHg without medication, and fasting glucose <100 mg/dL without medication.

^bPer 1,000 person-years, via Poisson regression.

^cAdjusted for age, sex, and race, via Cox proportional hazards regression.

Figure 1.

Cumulative incidence of venous thromboembolism (VTE) in relation to three categories of a Life’s Simple 7 Score, ARIC, 1987–2011

Limitations of this study include the inability to capture VTE events treated only in the outpatient setting; yet several pilot studies in ARIC have suggested that the vast majority of initial VTEs during 1987 to 2011 were hospitalized. We also examined Life’s Simple 7 at only a single time-point, but did so because we were interested in the potential impact of middle-age risk factors on subsequent VTE events.

In conclusion, this prospective study confirmed that greater adherence to ideal levels of AHA’s Life’s Simple 7 in middle age is associated with reduced risk of VTE later in life. This is important because Life’s Simple 7 guidelines were developed to prevent arterial CVD, not VTE, and because there are few strategies to prevent VTE other than prophylactic anticoagulation. Our findings and those from REGARDS [4] suggest that, if widely adopted by middle-age, adherence to Life’s Simple 7 may reduce the public health burden of VTE.