Critique 216: Strong effects of five lifestyle factors on risk of mortality and longevity of life – 31 May 2018

Li Y, Pan A, Wang DD, Liu X, Dhana K, Franco OH, Kaptoge S, Di Angelantonio E, Stampfer M, Willett WC. Hu FB. Impact of Healthy Lifestyle Factors on Life Expectancies in the US Population.  Circulation 2018;137:00–00. (Pre-publication). DOI: 10.1161/CIRCULATIONAHA.117.032047.

 Authors’ Abstract

BACKGROUND: Americans have a shorter life expectancy compared with residents of almost all other high-income countries. We aim to estimate the impact of lifestyle factors on premature mortality and life expectancy in the US population.

METHODS: Using data from the Nurses’ Health Study (1980–2014; n=78 865) and the Health Professionals Follow-up Study (1986–2014, n=44 354), we defined 5 low-risk lifestyle factors as never smoking, body mass index of 18.5 to 24.9 kg/m2, ≥30 min/d of moderate to vigorous physical activity, moderate alcohol intake, and a high diet quality score (upper 40%), and estimated hazard ratios for the association of total lifestyle score (0–5 scale) with mortality. We used data from the NHANES (National Health and Nutrition Examination Surveys; 2013–2014) to estimate the distribution of the lifestyle score and the US Centers for Disease Control and Prevention WONDER database to derive the age-specific death rates of Americans. We applied the life table method to estimate life expectancy by levels of the lifestyle score.

RESULTS: During up to 34 years of follow-up, we documented 42 167 deaths. The multivariable-adjusted hazard ratios for mortality in adults with 5 compared with zero low-risk factors were 0.26 (95% confidence interval [CI], 0.22–0.31) for all-cause mortality, 0.35 (95% CI, 0.27–0.45) for cancer mortality, and 0.18 (95% CI, 0.12–0.26) for cardiovascular disease mortality. The population-attributable risk of non-adherence to 5 low-risk factors was 60.7% (95% CI, 53.6–66.7) for all-cause mortality, 51.7% (95% CI, 37.1–62.9) for cancer mortality, and 71.7% (95% CI, 58.1–81.0) for cardiovascular disease mortality. We estimated that the life expectancy at age 50 years was 29.0 years (95% CI, 28.3–29.8) for women and 25.5 years (95% CI, 24.7–26.2) for men who adopted zero low-risk lifestyle factors. In contrast, for those who adopted all 5 low-risk factors, we projected a life expectancy at age 50 years of 43.1 years (95% CI, 41.3–44.9) for women and 37.6 years (95% CI, 35.8–39.4) for men. The projected life expectancy at age 50 years was on average 14.0 years (95% CI, 11.8–16.2) longer among female Americans with 5 low-risk factors compared with those with zero low-risk factors; for men, the difference was 12.2 years (95% CI, 10.1–14.2).

CONCLUSIONS: Adopting a healthy lifestyle could substantially reduce premature mortality and prolong life expectancy in US adults.

Forum Comments

The beneficial effects of many aspects of a “healthy lifestyle” have been known for more than a century, and throughout the latter part of the 20^th century, groups such as the American Heart Association have stressed the importance of a good diet, physical activity, and not smoking (as well as managing hypertension and dyslipidemia) in reducing the risk of cardiovascular disease.  However, the present study is especially important as it demonstrates the joint effects in large cohorts of subjects of five healthy lifestyle factors on disease-specific and total mortality over follow-up periods extending up to 34 years.

In these analyses, the reduction in the risk for premature mortality found for subjects meeting criteria for all five factors versus none was dramatic: an 84% reduction in all-cause mortality, 65% less cancer mortality, and 82% less cardiovascular disease mortality. Given that there were more than 42,000 deaths in their analyses, the authors were able to provide clear and rather precise estimates of the effect on mortality of such lifestyle factors.  The overall effect was associated with 12 to 14 additional years of life after age 50 for subjects meeting criteria for all five factors in comparison with subjects meeting none.  This study clearly indicates that the leading causes of premature death throughout the developed world are, to a large extent, preventable.

Specific comments from Forum members: Forum member Stockley wrote: “This is a well-executed analysis and well written paper.  It examined the relationship between five low-risk behaviours on CVD, cancer and all-cause mortality; the behaviours included moderate alcohol consumption defined as 5 to 15 g/day for women and 5 to 30 g/day for men.  The study’s findings are consistent with, and follow on nicely from, that of the US Centers for Disease Control and Prevention (CDC) analysis which examined the relationship between four low-risk behaviours and mortality; that study similarly concluded that moderate consumption of alcohol was considered as one of ‘four healthy lifestyle behaviours that exert a powerful and beneficial effect on mortality’ (Ford et al).

“Considering the potential dangers of excessive drinking, the CDC study authors also conducted sensitivity analyses omitting moderate alcohol use; the mortality risk for those who also consumed alcohol was significantly lower than for those having only the three other behaviours. Chiuve et al also included moderate alcohol consumption (5 to 30 g/day) as one of five low-risk behaviours associated with a reduced risk of coronary heart disease irrespective of concurrent medication for hypertension or hypercholesterolemia. These behaviours were based on the Healthy Eating Index (HEI), created by the US Department of Agriculture to assess how well the US population met dietary recommendations based on the Food Guide Pyramid and the Dietary Guidelines for Americans, The HEI defined moderate alcohol consumption of 1.5 to 2.5 drinks/day as ideal servings for men and 0.5 to 1.5 drinks/day as ideal for women on the basis of the lower risk of cardiovascular disease associated with moderate alcohol consumption (McCullough et al).

“In addition, Spencer et al included moderate alcohol consumption (up to 20 g/day) in their assessment of eight selected low-risk behaviours, where individuals with five or more of the selected low-risk behaviours had a lower risk of death from any cause within five years compared with those having less than five. More importantly, the study showed that while most individuals already have some healthy habits, almost all could make changes to their diet and lifestyle to improve their health.”

Forum member Teissedre wrote: “This is a very good and interesting paper taking into account several lifestyle factors on life expectancies including alcohol consumption. Authors found that adherence to 5 low-risk lifestyle-related could prolong life expectancy at age 50 years by 14.0 and 12.2 years for female and male US adults, respectively.  Moderate alcohol beverage drinking is a habit with beneficial effects on mortality, with added value to other factors.  The combinations of the healthy lifestyle factors are particularly efficient to obtain the longer potential prolonged life expectancy.”  Reviewer Ellison added: “The similarity in education and other socio-economic factors of the subjects in these studies tends to reduce potential confounding by such factors.”

Reviewer Goldfinger noted: “I too, agree with the importance of this paper and its conclusions. Those familiar with the Nurses’ Health Study and the Health Professionals Follow-up Study might have expected these findings/conclusions based upon their previous publications. Nevertheless, this robust body of data, at this time, presents a straightforward and cogent case for adopting a healthy lifestyle, which includes moderate and responsible daily alcohol consumption, for a longer and healthier life.  Physicians, often restrained by the possibilities of alcohol abuse, need to consider this message when counseling patients.”

Forum member Finkel stated: “This paper, not surprisingly, mirrors similar results we’ve seen and reviewed. One immediately comes to mind from investigators at the CDC in Atlanta (Ford et al), which embarrassed the ruling authorities and others because it clearly demonstrated epidemiologically that moderate drinking, among other lifestyle factors, is associated with enhanced health. The present paper lends additional embarrassment to that untiring faction of deniers. To my eye, the paper reflects fairly a soundly done study.”

Reviewer Van Velden commented: “This is a well written article, confirming the integrated approach to health. The various lifestyle factors must not be seen in isolation, but in conjunction with other healthy lifestyle factors.  This is especially true for alcohol consumption that must be seen as associated with a healthy diet, and an active lifestyle.  There is no doubt about smoking and obesity; and the metabolic syndrome is a serious threat to health in developed countries.  However, I think we have to focus more on chronic inflammation as an underlying pathophysiological factor.”

Stated Forum member de Gaetano: “This is really an important and well conducted study, supporting the conclusion that moderate alcohol drinking is an integral part of a healthy life style and contributes to significantly prolonging life expectancy at the age of 50 years. Also at the age of 70 – 80 the prolongation, though less important, is still significant. Unfortunately, at the age of 100 it does not matter if you did not smoke or consumed alcohol in moderation.  It will be interesting in future studies to measure whether the adherence to combined healthy lifestyle factors would also add life to years, not only years to life.”

Forum member Waterhouse raised an interesting (but unanswered) question: “I wonder if the study answers the question raised by the first line of the abstract: ‘Americans have a shorter life expectancy compared with residents of almost all other high-income countries.’ In other words, is the difference between US life expectancy and that of our peer countries explained by differences in these lifestyle factors?”

References from Forum critique

Chiuve SE, McCullough ML, Sacks FM, Rimm EB. Healthy lifestyle factors in the primary prevention of coronary heart disease among men: benefits among users and nonusers of lipid-lowering and antihypertensive medications. Circulation 2006;114:160-167.

Ford ES, Zhao G, Tsai J, Li C. Low-Risk Lifestyle Behaviors and All-Cause Mortality: Findings From the National Health and Nutrition Examination Survey III Mortality Study.  Am J Public Health 2011;101: 1922–1929.  doi:  10.2105/AJPH.2011.300167.

McCullough ML, Feskanich D, Stampfer MJ, Giovannucci EL, Rimm EB, Hu FB, Spiegelman D, Hunter DJ, Colditz GA. Willett WC. Diet quality and major chronic disease risk in men and women: moving toward improved dietary guidance.  Am J Clin Nutr 2002;76:1261-1271.

Spencer CA, Jamrozik K, Norman PE, Lawrence-Brown M. A simple lifestyle score predicts survival in healthy elderly men.  Prev Med 2005;40:712-717.

Forum Summary

It has long been known that a number of lifestyle factors – such as not smoking, being physically active, avoiding obesity – decrease the risk of many of the “diseases of ageing,” especially cardiovascular disease and cancer. The present paper from the Nurses’ Health Study and the Health Professionals Follow-up Study is especially important as it demonstrates the joint effects of five healthy factors on disease-specific and total mortality in very large cohorts of subjects. The “healthy lifestyle factors” evaluated were (1) never smoking, (2) body mass index of 18.5 to 24.9 kg/m2, (3) ≥30 min/d of moderate to vigorous physical activity, (4) moderate alcohol intake, and (5) a high diet quality score (upper 40%).  The similarity in education and other socio-economic factors of the subjects in these studies tends to reduce potential confounding by such factors.

There were more than 42,000 deaths in their cohorts during follow-up periods extending up to 34 years. The effects of these factors on subsequent risk of mortality were striking: for subjects meeting criteria for all five factors versus none, there was an 84% reduction in all-cause mortality, 65% less cancer mortality, and 82% less cardiovascular disease mortality. The overall effect was associated with 12 to 14 additional years of life after age 50 for subjects meeting criteria for all five factors.

Forum members consider this to be an excellent study, as it was based on data from very large cohorts of well-monitored subjects over many decades, with essentially full ascertainment of mortality. This study strongly suggests that the leading causes of premature death throughout the developed world are, to a large extent, preventable.

Reference: Li Y, Pan A, Wang DD, Liu X, Dhana K, Franco OH, Kaptoge S, Di Angelantonio E, Stampfer M, Willett WC. Hu FB.  Impact of Healthy Lifestyle Factors on Life Expectancies in the US Population.  Circulation 2018;137:00–00. (Pre-publication).  DOI: 10.1161/CIRCULATIONAHA.117.032047.

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 Comments on this critique by the International Scientific Forum on Alcohol Research were provided by the following members:

Andrew L. Waterhouse, PhD, Department of Viticulture and Enology, University of California, Davis, USA

David Van Velden, MD, Dept. of Pathology, Stellenbosch University, Stellenbosch, South Africa

Fulvio Ursini, MD, Dept. of Biological Chemistry, University of Padova, Padova, Italy

Pierre-Louis Teissedre, PhD, Faculty of Oenology–ISVV, University Victor Segalen Bordeaux 2, Bordeaux, France

Arne Svilaas, MD, PhD, general practice and lipidology, Oslo University Hospital, Oslo, Norway

Creina Stockley, PhD, MSc Clinical Pharmacology, MBA; Health and Regulatory Information Manager, Australian Wine Research Institute, Glen Osmond, South Australia, Australia

Tedd Goldfinger, DO, FACC, Desert Cardiology of Tucson Heart Center, University of Arizona School of Medicine, Tucson, AZ, USA

Giovanni de Gaetano, MD, PhD, Department of Epidemiology and Prevention, IRCCS Istituto Neurologico Mediterraneo NEUROMED, Pozzilli, Italy

Harvey Finkel, MD, Hematology/Oncology, Retired (Formerly, Clinical Professor of Medicine, Boston University Medical Center, Boston, MA, USA)

R. Curtis Ellison, MD, Professor of Medicine, Section of Preventive Medicine & Epidemiology, Boston University School of Medicine, Boston, MA, USA