Lifestyle risk factors and residual life expectancy at age 40: a German cohort study

Abstract

Background: Cigarette smoking, adiposity, unhealthy diet, heavy alcohol drinking and physical inactivity together are associated with about half of premature deaths in Western populations. The aim of this study was to estimate their individual and combined impacts on residual life expectancy (RLE).

Methods: Lifestyle and mortality data from the EPIC-Heidelberg cohort, comprising 22,469 German adults ≥40 years and free of diabetes, cardiovascular disease and cancer at recruitment (1994-1998), were analyzed with multivariable Gompertz proportional hazards models to predict lifetime survival probabilities given specific baseline status of lifestyle risk factors. The life table method was then used to estimate the RLEs.

Results: For 40-year-old adults, the most significant loss of RLE was associated with smoking (9.4 [95% confidence interval: 8.3, 10.6] years for male and 7.3 [6.0, 8.9] years for female heavy smokers [>10 cigarettes/day]; 5.3 [3.6, 7.1] years for men and 5.0 [3.2, 6.6] years for women smoking ≤10 cigarettes/day). Other lifestyle risk factors associated with major losses of RLE were low body mass index (BMI <22.5 kg/m(2), 3.5 [1.8, 5.1] years for men; 2.1 [0.5, 3.6] years for women), obesity (BMI ≥30, 3.1 [1.9, 4.4] years for men; 3.2 [1.8, 5.1] years for women), heavy alcohol drinking (>4 drinks/day, 3.1 [1.9, 4.0] years for men), and high processed/red meat consumption (≥120 g/day, 2.4 [1.0, 3.9] years for women). The obesity-associated loss of RLE was stronger in male never smokers, while the loss of RLE associated with low BMI was stronger in current smokers. The loss of RLE associated with low leisure time physical activity was moderate for women (1.1 [0.05, 2.1] years) and negligible for men (0.4 [-0.3, 1.2] years). The combined loss of RLE for heavy smoking, obesity, heavy alcohol drinking and high processed/red meat consumption, versus never smoking, optimal BMI (22.5 to 24.9), no/light alcohol drinking and low processed/red meat consumption, was 17.0 years for men and 13.9 years for women.

Conclusions: Promoting healthy lifestyles, particularly no cigarette smoking and maintaining healthy body weight, should be the core component of public health approaches to reducing premature deaths in Germany and similar affluent societies.

Figure 1

Overall survival curves (Gompertz PH models, observed data, and the German life table) and two survival curves for the healthy and the unhealthy combination of lifestyle risk factors, respectively, the EPIC-Heidelberg cohort^a.^aParticipants with pre-existing diabetes, cardiovascular disease or cancer were excluded. The healthy combination: never smoking, optimal BMI (22.5 to 24.9), no/light alcohol drinking and low processed/red meat consumption; the unhealthy combination: heavy smoking (>10 cigarettes/day), obesity (BMI ≥30), heavy alcohol drinking (>4 drinks/day for men and >1 drink/day for women) and high processed/red meat consumption (≥120 g/day). Other factors remained identical for these two groups and were fixed at their assumedly healthy level. BMI, body mass index; EPIC, European Prospective Investigation into Cancer and Nutrition; PH, proportional hazards.