Muscular strength and adiposity as predictors of adulthood cancer mortality in men

Abstract

Background: We examined the associations between muscular strength, markers of overall and central adiposity, and cancer mortality in men.

Methods: A prospective cohort study including 8,677 men ages 20 to 82 years followed from 1980 to 2003. Participants were enrolled in The Aerobics Centre Longitudinal Study, the Cooper Institute in Dallas, Texas. Muscular strength was quantified by combining 1-repetition maximal measures for leg and bench presses. Adiposity was assessed by body mass index (BMI), percent body fat, and waist circumference.

Results: Cancer death rates per 10,000 person-years adjusted for age and examination year were 17.5, 11.0, and 10.3 across incremental thirds of muscular strength (P = 0.001); 10.9, 13.4, and 20.1 across BMI groups of 18.5-24.9, 25.0-29.9, and > or =30 kg/m(2), respectively (P = 0.008); 11.6 and 17.5 for normal (<25%) and high percent body fat (> or =25%), respectively (P = 0.006); and 12.2 and 16.7 for normal (< or =102 cm) and high waist circumference (>102 cm), respectively (P = 0.06). After adjusting for additional potential confounders, hazard ratios (95% confidence intervals) were 1.00 (reference), 0.65 (0.47-0.90), and 0.61 (0.44-0.85) across incremental thirds of muscular strength, respectively (P = 0.003 for linear trend). Further adjustment for BMI, percent body fat, waist circumference, or cardiorespiratory fitness had little effect on the association. The associations of BMI, percent body fat, or waist circumference with cancer mortality did not persist after further adjusting for muscular strength (all P > or = 0.1).

Conclusions: Higher levels of muscular strength are associated with lower cancer mortality risk in men, independent of clinically established measures of overall and central adiposity, and other potential confounders.

Figures

Figure 1

Joint association of muscular strength and (1A) body mass index (BMI), (1B) percent body fat, (1C) waist circumference, and (1D) cardiorespiratory fitness with the age- and examination year-adjusted rates of cancer mortality, Aerobics Center Longitudinal Study, 1980-2003. Error bars represent standard error. Likelihood ratio test for interaction, χ2df=1 = 0.70, P = 0.40 for BMI-strength, χ2df=1 = 0.51, P = 0.48 for percent body fat-strength, χ2df=1 = 0.77, P = 0.38 for waist circumference-strength, and χ2df=1 = 1.74, P = 0.19 for cardiorespiratory fitness-strength. Black bars represent the lowest third; grey bars, the middle third; and white bars, the upper third of baseline muscular strength. Numbers under the bar are sample size (deaths from cancer).

Figure 1

Joint association of muscular strength and (1A) body mass index (BMI), (1B) percent body fat, (1C) waist circumference, and (1D) cardiorespiratory fitness with the age- and examination year-adjusted rates of cancer mortality, Aerobics Center Longitudinal Study, 1980-2003. Error bars represent standard error. Likelihood ratio test for interaction, χ2df=1 = 0.70, P = 0.40 for BMI-strength, χ2df=1 = 0.51, P = 0.48 for percent body fat-strength, χ2df=1 = 0.77, P = 0.38 for waist circumference-strength, and χ2df=1 = 1.74, P = 0.19 for cardiorespiratory fitness-strength. Black bars represent the lowest third; grey bars, the middle third; and white bars, the upper third of baseline muscular strength. Numbers under the bar are sample size (deaths from cancer).

Figure 1

Joint association of muscular strength and (1A) body mass index (BMI), (1B) percent body fat, (1C) waist circumference, and (1D) cardiorespiratory fitness with the age- and examination year-adjusted rates of cancer mortality, Aerobics Center Longitudinal Study, 1980-2003. Error bars represent standard error. Likelihood ratio test for interaction, χ2df=1 = 0.70, P = 0.40 for BMI-strength, χ2df=1 = 0.51, P = 0.48 for percent body fat-strength, χ2df=1 = 0.77, P = 0.38 for waist circumference-strength, and χ2df=1 = 1.74, P = 0.19 for cardiorespiratory fitness-strength. Black bars represent the lowest third; grey bars, the middle third; and white bars, the upper third of baseline muscular strength. Numbers under the bar are sample size (deaths from cancer).

Figure 1

Joint association of muscular strength and (1A) body mass index (BMI), (1B) percent body fat, (1C) waist circumference, and (1D) cardiorespiratory fitness with the age- and examination year-adjusted rates of cancer mortality, Aerobics Center Longitudinal Study, 1980-2003. Error bars represent standard error. Likelihood ratio test for interaction, χ2df=1 = 0.70, P = 0.40 for BMI-strength, χ2df=1 = 0.51, P = 0.48 for percent body fat-strength, χ2df=1 = 0.77, P = 0.38 for waist circumference-strength, and χ2df=1 = 1.74, P = 0.19 for cardiorespiratory fitness-strength. Black bars represent the lowest third; grey bars, the middle third; and white bars, the upper third of baseline muscular strength. Numbers under the bar are sample size (deaths from cancer).