The VITamin D and OmegA-3 TriaL (VITAL): rationale and design of a large randomized controlled trial of vitamin D and marine omega-3 fatty acid supplements for the primary prevention of cancer and cardiovascular disease

Data from laboratory studies, observational research, and/or secondary prevention trials suggest that vitamin D and marine omega-3 fatty acids may reduce risk for cancer or cardiovascular disease (CVD), but primary prevention trials with adequate dosing in general populations (i.e., unselected for disease risk) are lacking. The ongoing VITamin D and OmegA-3 TriaL (VITAL) is a large randomized, double-blind, placebo-controlled, 2 x 2 factorial trial of vitamin D (in the form of vitamin D(3) [cholecalciferol], 2000 IU/day) and marine omega-3 fatty acid (Omacor fish oil, eicosapentaenoic acid [EPA]+docosahexaenoic acid [DHA], 1g/day) supplements in the primary prevention of cancer and CVD among a multi-ethnic population of 20,000 U.S. men aged ≥ 50 and women aged ≥ 55. The mean treatment period will be 5 years. Baseline blood samples will be collected in at least 16,000 participants, with follow-up blood collection in about 6000 participants. Yearly follow-up questionnaires will assess treatment compliance (plasma biomarker measures will also assess compliance in a random sample of participants), use of non-study drugs or supplements, occurrence of endpoints, and cancer and vascular risk factors. Self-reported endpoints will be confirmed by medical record review by physicians blinded to treatment assignment, and deaths will be ascertained through national registries and other sources. Ancillary studies will investigate whether these agents affect risk for diabetes and glucose intolerance; hypertension; cognitive decline; depression; osteoporosis and fracture; physical disability and falls; asthma and other respiratory diseases; infections; and rheumatoid arthritis, systemic lupus erythematosus, thyroid diseases, and other autoimmune disorders.

Physical activity and cardiovascular disease prevention in women: a review of the epidemiologic evidence

Epidemiologic studies suggest that as little as 30minutes of moderate-intensity physical activity per day can lower the risk of developing cardiovascular disease in women. Sedentary individuals who become physically active even at older ages derive cardiovascular benefits. Physical activity appears to slow the initiation and progression of CVD through salutary effects not only on adiposity but also on insulin sensitivity, glycemic control, incident type 2 diabetes, blood pressure, lipids, endothelial function, hemostasis, and inflammatory defense systems. Public health initiatives that promote moderate increases in physical activity may offer the best balance between efficacy and feasibility to improve cardiovascular health in sedentary populations.

Does vitamin D protect against cardiovascular disease?

Because of its role in maintaining bone density, vitamin D has long been recognized as critical to the health of women, a group at disproportionate risk of osteoporosis. Recent data from epidemiologic and laboratory studies suggest that vitamin D may also protect against the development of cardiovascular and other chronic diseases. Because three quarters of US women (and men) have suboptimal vitamin D status, many experts advocate increasing daily recommended intakes from 200-600 IU to at least 1,000 IU, which may indeed be a prudent strategy. However, data from large randomized clinical trials testing sufficiently high doses of this vitamin for cardiovascular disease prevention--as well as to assess the overall balance of benefits and risks of such supplementation--are needed.

Reassessing Benefits and Risks of Hormone Therapy

Recent randomized clinical trials of postmenopausal hormone therapy have informed clinical decision making and provided insights that help identify appropriate candidates for treatment. A decline in the use of hormone therapy began precipitously in 2002 with publication of data from the Women's Health Initiative. This review examines the scientific literature surrounding this major change in practice and comments on the equilibrating process now taking place. Notably, the incidence of most of the medical conditions adversely affected by hormone therapy increases with age. As a result, recently menopausal women—those most interested in using hormone therapy—are at lower absolute risk of adverse events than older women. A critical mass of data now suggests that age and time since menopause may also modify relative risks of selected outcomes with use of hormone therapy, but this warrants further study. Duration of hormone therapy use also appears to influence risk, with the occurrence of certain outcomes (such as venous thrombosis) being highest in the first 1 or 2 years of hormone therapy use and others (such as breast cancer) increasing with longer duration of hormone therapy use. The conflicting results for some outcomes from the estrogen arm and the estrogen-progestin arm of the Women's Health Initiative suggest that progestins influence risk of several diseases, particularly breast cancer. Quantifying the benefits and risks of estrogen and estrogen-progestin by age group makes it possible to discuss pros and cons of hormone therapy in a more clinically relevant manner with patients. Hormone therapy remains a viable short-term option for the management of moderate to severe vasomotor symptoms in recently menopausal women who are in generally good health. However, due to known risks, it should not be initiated or continued for the express purpose of preventing cardiovascular disease or other chronic diseases.

Invited commentary: hormone therapy and risk of coronary heart disease why renew the focus on the early years of menopause?

After the initial report from the Women's Health Initiative estrogen-progestin trial, which found that menopausal hormone therapy was associated with an increased risk of coronary heart disease in the overall cohort (age range: 50-79 years; mean age: 63 years), researchers took a closer look at the data from this and other studies, focusing on the timing of initiation of such therapy. The results suggest that hormone therapy may have a beneficial effect on the heart if started in early menopause, when a woman's arteries are still likely to be relatively healthy, but a harmful effect if started in late menopause, when advanced atherosclerosis may be present. The implication of the timing hypothesis for clinical practice is not that recently menopausal women be given hormone therapy for coronary heart disease prevention but rather that clinicians can be reassured about cardiac risks when considering short-term use of hormone therapy for vasomotor symptom relief in such women. The reduction in vasomotor symptoms must be weighed against other risks and benefits of treatment, but coronary disease is typically not a major factor in the equation for women who are recently menopausal.

Social engagement and depressive symptoms in late life: longitudinal findings

OBJECTIVE

The purpose is to investigate whether social engagement protects against depressive symptoms in older adults.

METHOD

Three waves of data from a representative cohort study of community-dwelling adults aged 65 years and above from the New Haven Established Populations for the Epidemiologic Study of the Elderly are examined using random effects models.

RESULTS

Social engagement (an index combining social and productive activity) is associated with lower CES-D scores after adjustment for age, sex, time, education, marital status, health and functional status, and fitness activities. This association is generally constant with time, suggesting a cross-sectional association. In addition, social engagement is associated with change in depressive symptoms, but only among those with CES-D scores below 16 at baseline.

DISCUSSION

Social engagement is independently associated with depressive symptoms cross-sectionally. A longitudinal association is seen only among those not depressed at baseline.

Postmenopausal hormone therapy: new questions and the case for new clinical trials

Observational studies suggest that postmenopausal hormone therapy (HT) prevents coronary heart disease, whereas randomized clinical trials have not confirmed a cardioprotective effect. Although observational studies may have overestimated the coronary benefit conferred by postmenopausal hormone use, there are other plausible explanations for the apparent discrepancy between previous results and the less favorable findings from clinical trials such as the large Women's Health Initiative. There is now a critical mass of data to support the hypothesis that age or time since menopause may importantly influence the benefit-risk ratio associated with HT, especially with respect to cardiovascular outcomes, and that the method of administration, dose, and formulation of exogenous hormones may also be relevant. Although the weight of the evidence indicates that older women and those with subclinical or overt coronary heart disease should not take HT, estrogen remains the most effective treatment currently available for vasomotor symptoms, and its effects on the development of coronary disease in newly postmenopausal women remain unclear. Moreover, effects of HT on quality of life and cognitive function in recently postmenopausal women merit further study. These unresolved clinical issues provide the rationale for the design of the Kronos Early Estrogen Prevention Study, a 5-year randomized trial that will evaluate the effectiveness of low-dose oral estrogen and transdermal estradiol in preventing progression of atherosclerosis in recently postmenopausal women.

Epidemiological evidence for the role of physical activity in reducing risk of type 2 diabetes and cardiovascular disease

Epidemiological studies suggest that physically active individuals have a 30-50% lower risk of developing type 2 diabetes than do sedentary persons and that physical activity confers a similar risk reduction for coronary heart disease. Risk reductions are observed with as little as 30 min of moderate-intensity activity per day. Protective mechanisms of physical activity include the regulation of body weight; the reduction of insulin resistance, hypertension, atherogenic dyslipidemia, and inflammation; and the enhancement of insulin sensitivity, glycemic control, and fibrinolytic and endothelial function. Public health initiatives promoting moderate increases in physical activity may offer the best balance between efficacy and feasibility to improve metabolic and cardiovascular health in largely sedentary populations.

High-sensitivity C-reactive protein: clinical importance

High-sensitivity C-reactive protein (hsCRP) is a marker of inflammation that predicts incident myocardial infarction, stroke, peripheral arterial disease, and sudden cardiac death among healthy individuals with no history of cardiovascular disease, and recurrent events and death in patients with acute or stable coronary syndromes. hsCRP confers additional prognostic value at all levels of cholesterol, Framingham coronary risk score, severity of the metabolic syndrome, and blood pressure, and in those with and without subclinical atherosclerosis. hsCRP levels of less than 1, 1 to 3, and greater than 3 mg/L are associated with lower, moderate, and higher cardiovascular risks, respectively. This article summarizes epidemiologic data on the relation between CRP and atherothrombotic disease and provides clinical guidelines for hsCRP screening in cardiovascular risk assessment.

The Women's Antioxidant Cardiovascular Study: Design and Baseline Characteristics of Participants

BACKGROUND

The evidence for a potential benefit of antioxidant vitamins and folic acid in cardiovascular disease (CVD) prevention is derived from laboratory, clinical, and observational epidemiological studies but remains inconclusive. Large-scale randomized trials with clinical end points are necessary to minimize confounding and provide unbiased estimates of the balance of benefits and risks, yet data from such trials are scarce, especially among women.

METHODS

The Women's Antioxidant Cardiovascular Study (WACS) is a randomized, double-blind, placebo-controlled trial testing whether antioxidant vitamins and a folic acid/vitamin B(6)/vitamin B(12) combination prevent future cardiovascular events among women with preexisting CVD or >or=3 CVD risk factors. This paper describes the design of the trial and baseline characteristics of participants, evaluates the success of randomization, and addresses the generalizability of future findings.

RESULTS

In a factorial design, 8171 U.S. female health professionals aged >or=40 years were randomized to vitamin E, vitamin C, beta-carotene, or placebos. Of these women, 5442 were also subsequently randomized to folic acid/vitamin B(6)/vitamin B(12) or placebo. The randomization was successful, as evidenced by similar distributions of baseline demographic, health, and behavioral characteristics across treatment groups. The clinical profile of participants was similar to that observed in another large trial of women with CVD.

CONCLUSIONS

The similar distribution of known potential confounders across treatment groups provides reassurance that unmeasured or unknown potential confounders are also equally distributed. Although a definitive conclusion regarding generalizability requires additional trials in diverse populations, there is little biological basis for supposing that the benefit-risk balance differs in other high-risk women.

Physical Activity and Cardiovascular Disease Prevention in Women: How Much Is Good Enough?

Epidemiologic data suggest that 30 min x d(-1) of brisk walking can reduce cardiovascular disease incidence in women and men. In a sedentary society, public health initiatives that promote moderate increases in physical activity may represent the optimal balance between efficacy, feasibility, and safety to achieve the desired cardioprotective effect.

Characteristics of the Modified Mini-Mental State Exam among elderly persons

This study assesses psychometric properties of the Modified Mini-Mental State Exam (3MS) and present population norms and demographic risk factors for low 3MS scores. The subjects were 885 persons aged 65 and older who took the 3MS as part of the Stirling County Study, a population-based longitudinal study of adult residents of a county in Atlantic Canada. 3MS scores were not dependent on the specific rater who scored the test; thus, the 3MS is free of rater bias. Interrater reliability was high (intraclass correlation coefficient=0.98), as was internal consistency (coefficient alpha=0.91). Test-retest reliability over 3 years was 0.78. One third of subjects tested as cognitively impaired. Risk factors for low scores include older age, less education, male gender, and examination in French. The correlation between 3MS and Mini Mental State Exam scores was 0.95. The 3MS can be used as an epidemiologic measure of global cognitive performance among elderly persons.

Physical activity and the prevention of cardiovascular disease

This article summarizes recent evidence on the role of physical activity in the prevention of overt and subclinical vascular disease. Epidemiologic data suggest that as little as 30 minutes per day of moderate-intensity physical activity, including brisk walking, reduces the incidence of clinical cardiovascular events in men and women. Regular exercise may also retard the progression of asymptomatic coronary and peripheral arteriosclerosis. Cardioprotective mechanisms of physical activity include reducing adiposity, blood pressure, diabetes incidence, dyslipidemia, and inflammation, and enhancing insulin sensitivity, glycemic control, fibrinolysis, and endothelial function. In a sedentary society such as the United States, public health initiatives that promote moderate increases in activity represent the optimal balance between efficacy and feasibility to achieve desired improvements in cardiovascular health.

Does vitamin E supplementation prevent cardiovascular events?

In recent years, vitamin E has been investigated as a cardioprotective agent. Experimental studies have identified potential mechanisms by which vitamin E may inhibit the development of atherosclerosis, and observational studies of individuals without coronary disease suggest that vitamin E intake may prevent future cardiovascular events. Secondary prevention trials to date have demonstrated little benefit from vitamin E supplementation. It remains possible, however, that supplementation may be useful among certain high-risk groups, including those with nutritional deficiencies. Limited data from completed primary prevention trials also indicate minimal cardioprotection from vitamin E, but large-scale trials now in progress may yet show benefit. Results from ongoing trials will contribute powerfully to the totality of evidence on which to formulate both appropriate clinical recommendations for individual patients and a rational public health policy for the population as a whole. At this time, there is insufficient evidence for issuing a public health recommendation to use vitamin E supplements to prevent cardiovascular disease (CVD). Rather, increased intake of fruits, vegetables, and other antioxidant-rich foods should be promoted as part of a healthy diet because they provide nutritional benefits beyond any potential antioxidant effect. Moreover, even if found to reduce CVD risk, vitamin supplement use should be considered an adjunct, not an alternative, to established cardioprotective measures, such as smoking abstention, avoidance of obesity, adequate physical activity, and control of high blood pressure and hyperlipidemia.

Socioeconomic status and mortality among the elderly: findings from four US communities

The effect of socioeconomic status (SES) on mortality was examined in the community-dwelling elderly. Data were obtained from four population-based studies that enrolled elderly residents of four US communities (East Boston, Massachusetts; New Haven, Connecticut; east-central Iowa; and the Piedmont region of North Carolina) and followed them for 9 years, starting in 1982 or 1986. Higher SES, whether measured by education, by household income, or by occupational prestige, was generally associated with lower mortality. However, the pattern of findings varied by gender and by community. For men, all three SES indicators were associated with mortality in the majority of cohorts. For women, this was true only for income. SES-mortality associations were attenuated but not eliminated after adjustment for behavior and health status. SES-mortality associations were stronger in New Haven and North Carolina than in East Boston and Iowa. The latter communities are more homogeneous with respect to ethnicity, urbanization, and occupational history than the former. Future research should investigate the relative validity of traditional SES measures for men and women and develop more balanced assessment methods. These findings also suggest that it is important to consider not only individual characteristics but also community attributes that mediate or modify the pathways through which socioeconomic conditions may influence health.

Cognitive impairment and mortality in the community-dwelling elderly

The effects on mortality of cognitive impairment and 3-year declines in cognitive function were examined among community-dwelling adults aged 68 years or more. Data were taken from a population-based cohort study that enrolled noninstitutionalized elderly residents of New Haven, Connecticut, and followed them by conducting in-home interviews in 1982, 1985, 1988, and 1994. The cognitive function of 1,997 respondents was assessed by using the 30-point Mini-Mental State Examination in 1985; 1,372 respondents (86% of those alive) were retested in 1988. Responses were classified as high normal (28-30), low normal (24-27), mild impairment (18-23), or severe impairment (0-17); cognitive decline was defined as a transition to a lower category. After control for multiple potential confounders, both severe and mild cognitive impairment were strongly predictive of subsequent mortality among respondents aged less than 80 years. Upon closer examination, the elevated mortality risk was observed primarily among respondents whose cognitive decline was recent rather than among those whose cognitive performance was compromised but stable. Among respondents aged 80 years or more, declines to severe cognitive impairment were predictive of mortality, but it was not clear whether the decline per se signaled an unfavorable prognosis not accounted for by the resulting impairment level. Cognitive declines, especially those in the young elderly, have a marked adverse impact on survival.

Social disengagement and incident cognitive decline in community-dwelling elderly persons

BACKGROUND

Social engagement, which is defined as the maintenance of many social connections and a high level of participation in social activities, has been thought to prevent cognitive decline in elderly persons. However, few longitudinal studies of this relation have been done.

OBJECTIVE

To determine the relation between social disengagement and incident cognitive decline in community-dwelling elderly persons.

DESIGN

Cohort study.

SETTING

New Haven, Connecticut.

PARTICIPANTS

2812 noninstitutionalized elderly persons (65 years of age or older) who were interviewed in their homes in 1982, 1985, 1988, and 1994.

MEASUREMENTS

A global social disengagement scale was constructed from the following indicators: presence of a spouse, monthly visual contact with three or more relatives or friends, yearly nonvisual contact with 10 or more relatives or friends, attendance at religious services, group membership, and regular social activities. Cognitive function was assessed with the Short Portable Mental Status Questionnaire. Response to the questionnaire was scored as high, medium, or low. Cognitive decline was defined as a transition to a lower category.

RESULTS

Compared with persons who had five or six social ties, those who had no social ties were at increased risk for incident cognitive decline after adjustment for age, initial cognitive performance, sex, ethnicity, education, income, housing type, physical disability, cardiovascular profile, sensory impairment, symptoms of depression, smoking, alcohol use, and level of physical activity. The 3-year odds ratio was 2.24 (95% CI, 1.40 to 3.58; P < 0.001), the 6-year odds ratio was 1.91 (CI, 1.14 to 3.18; P = 0.01), and the 12-year odds ratio was 2.37 (CI, 1.07 to 4.88; P = 0.03).

CONCLUSION

Social disengagement is a risk factor for cognitive impairment among elderly persons.

Depressive symptomatology and incident cognitive decline in an elderly community sample

BACKGROUND

It is not known whether depression is a cause or consequence of progressive cognitive decline. We assessed the relationship between depressive symptoms and subsequent cognitive decline in the community-dwelling elderly population.

METHODS

Data were from a population-based cohort study that enrolled 2812 noninstitutionalized elderly residents of New Haven, Conn, and followed them with in-home visits in 1982, 1985, 1988, and 1994. Cognitive function was assessed with the Short Portable Mental Status Questionnaire (SPMSQ). Response to the SPMSQ was scored as high, medium, and low, and cognitive decline was defined as a transition to a lower category. Depressive symptoms were measured with the Center for Epidemiological Studies Depression Scale.

RESULTS

An elevated level of depressive symptoms was associated with an increased risk of incident cognitive decline among medium SPMSQ performers (3-year odds ratio [OR], 1.72; 95% confidence interval [CI], 1.04-2.82, P=.03; 6-year OR, 2.40; 95% CI, 1.33-4.34; P=.004; 12-year OR, 1.65; 95% CI, 0.62-4.38; P=.31) but not among high performers (3-year OR, 0.93; 95% CI, 0.62-1.39; P=.71; 6-year OR, 1.03; 95% CI, 0.67-1.58; P=.90; 12-year OR, 1.26; 95% CI, 0.59-2.71; P=.55), after adjustment for age, sex, race, education, income, housing type, functional disability, cardiovascular profile, and alcohol use.

CONCLUSIONS

Depressive symptoms, particularly dysphoric mood, presage future cognitive losses among elderly persons with moderate cognitive impairments. However, the data do not provide support for the hypothesis that depressive symptoms are associated with the onset or rate of cognitive decline among cognitively intact elderly persons.