Anthropometry and esophageal cancer risk in the European prospective investigation into cancer and nutrition

BACKGROUND

Increasing evidence suggests that general obesity [measured by body mass index (BMI)] is positively associated with risk of esophageal adenocarcinoma (EAC). In contrast, previous studies have shown inverse relations with esophageal squamous cell carcinoma (ESCC). However, it is still unclear whether body fat distribution, particularly abdominal obesity, is associated with each type of esophageal cancer.

METHODS

We applied multivariable adjusted Cox proportional hazards regression to investigate the association between anthropometric measures and risk of EAC and ESCC among 346,554 men and women participating in the European Prospective Investigation into Cancer and Nutrition. All statistical tests were two sided.

RESULTS

During 8.9 years of follow-up, we documented 88 incident cases of EAC and 110 cases of ESCC. BMI, waist circumference, and waist-to-hip ratio (WHR) were positively associated with EAC risk [highest versus lowest quintile; relative risk (RR), 2.60; 95% confidence interval (95% CI), 1.23-5.51; P(trend) < 0.01; RR, 3.07; 95% CI, 1.35-6.98; P(trend) < 0.003; and RR, 2.12; 95% CI, 0.98-4.57; P(trend) < 0.004]. In contrast, BMI and waist circumference were inversely related to ESCC risk, whereas WHR showed no association with ESCC. In stratified analyses, BMI and waist circumference were significantly inversely related to ESCC only among smokers but not among nonsmokers. However, when controlled for BMI, we found positive associations for waist circumference and WHR with ESCC, and these associations were observed among smokers and nonsmokers.

CONCLUSION

General and abdominal obesity were associated with higher EAC risk. Further, our study suggests that particularly an abdominal body fat distribution might also be a risk factor for ESCC.

General and abdominal adiposity and risk of death in Europe

BACKGROUND

Previous studies have relied predominantly on the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) to assess the association of adiposity with the risk of death, but few have examined whether the distribution of body fat contributes to the prediction of death.

METHODS

We examined the association of BMI, waist circumference, and waist-to-hip ratio with the risk of death among 359,387 participants from nine countries in the European Prospective Investigation into Cancer and Nutrition (EPIC). We used a Cox regression analysis, with age as the time variable, and stratified the models according to study center and age at recruitment, with further adjustment for educational level, smoking status, alcohol consumption, physical activity, and height.

RESULTS

During a mean follow-up of 9.7 years, 14,723 participants died. The lowest risks of death related to BMI were observed at a BMI of 25.3 for men and 24.3 for women. After adjustment for BMI, waist circumference and waist-to-hip ratio were strongly associated with the risk of death. Relative risks among men and women in the highest quintile of waist circumference were 2.05 (95% confidence interval [CI], 1.80 to 2.33) and 1.78 (95% CI, 1.56 to 2.04), respectively, and in the highest quintile of waist-to-hip ratio, the relative risks were 1.68 (95% CI, 1.53 to 1.84) and 1.51 (95% CI, 1.37 to 1.66), respectively. BMI remained significantly associated with the risk of death in models that included waist circumference or waist-to-hip ratio (P<0.001).

CONCLUSIONS

These data suggest that both general adiposity and abdominal adiposity are associated with the risk of death and support the use of waist circumference or waist-to-hip ratio in addition to BMI in assessing the risk of death.

Improved physical fitness of cancer survivors: a randomised controlled trial comparing physical training with physical and cognitive-behavioural training

We compared the effect of a group-based 12-week supervised exercise programme, i.e. aerobic and resistance exercise, and group sports, with that of the same programme combined with cognitive-behavioural training on physical fitness and activity of cancer survivors. One hundred and forty seven cancer survivors (all cancer types, medical treatment >or=3 months ago)were randomly assigned to physical training (PT, n=71) or PT plus cognitive-behavioural training (PT+CBT, n=76). Maximal aerobic capacity, muscle strength and physical activity were assessed at baseline and post-intervention. Analyses using multilevel linear mixed-effects models showed that cancer survivors' physical fitness increased significantly in PT and PT+CBT from baseline to post-intervention. Changes did not differ between PT and PT+CBT. Physical fitness of cancer survivors was improved following an intensive physical training programme. Adding a structured cognitive-behavioural intervention did not enhance the effect.

The development of an evidence-based physical self-management rehabilitation programme for cancer survivors

OBJECTIVE

This paper describes the development of a physical training programme for cancer patients. Four related but conceptually and empirically distinct physical problems are described: decreased aerobic capacity, decreased muscle strength, fatigue and impaired role physical functioning. The study aimed to identify the optimal content for an exercise programme that addresses these four physical problems, based on the highest level of evidence available. The study further aimed to review the evidence available on the delivery of the programmes. The final goal was to develop a programme in which content and delivery are based on the best available evidence.

METHODS

Literature searches (PUBMED and MEDLINE, to July 2006) on content looked for evidence about the efficacy of exercise on aerobic capacity, muscle strength, fatigue and impaired role physical functioning. Literature searches on delivery looked for self-management and/or self-efficacy enhancing techniques in relation to outcome, adherence to and/or adoption of a physically active lifestyle.

RESULTS

Evidence on the effectiveness of exercise in cancer patients varies and increases when moving from muscle strength (RCT level), fatigue and physical role functioning to aerobic capacity (all at the meta-analysis level). Effect sizes for aerobic capacity were moderate, while effect sizes for fatigue and physical role functioning were zero and/or small. Many of the studies have significant methodological shortcomings. There was some evidence (meta-analyses) that self-management programmes and self-efficacy enhancing programmes have beneficial effects on health outcomes in a variety of chronic diseases, on the quality of life in cancer patients, and on exercise adherence and later exercise behaviour.

CONCLUSION

Limited data are available on the effectiveness of exercise for cancer patients. Although evidence supports the positive effects of exercise on exercise capacity during and after completion of cancer treatment, the effects for fatigue and role functioning are ambiguous. Evidence on the effectiveness of progressive exercise training on muscle strength is promising. In addition, some evidence supports the positive effects of self-management programmes and self-efficacy enhancing programmes on health outcomes, exercise adherence and later exercise behaviour.

PRACTICE IMPLICATIONS

The resulting programme was developed on the basis of the highest quality of evidence available regarding content and delivery. The content is based on information obtained from the present review, and on the recommendations of the American College of Sports Medicine. Potential advantages of the programme include: (a) tailored physical training towards focusing on the patient's established problems and (b) delivery of the training as a self-management programme that might have beneficial effects on health outcome, exercise adherence and a long-term physically active lifestyle.

Muscle function during repetitive moderate-intensity muscle contractions in myoadenylate deaminase-deficient Dutch subjects

We investigated whether the capacity for repetitive submaximal muscle contraction was reduced in a group of subjects (n=8) with a primary deficiency of myoadenylate deaminase (MAD). Quadriceps femoris muscle fatigue was evaluated using voluntary and electrically stimulated contractions during 20 min of repetitive voluntary isometric contractions at 40% of maximal force-generating capacity (MFGC). After 5 min of exercise, MFGC had declined significantly to 70.6+/-4.1% (mean+/-S.E.M.) and 87.2+/-1.6% of baseline values in MAD-deficient and sedentary control subjects (n=8) respectively (P=0.002 between groups). After 5 min of exercise, the half-relaxation time had increased significantly to 113.4+/-6.1% of baseline in MAD-deficient muscle, but had decreased significantly to 94.1+/-1.3% in control subjects (P=0.003 between groups). All control subjects completed the 20-min exercise test. Five of the MAD-deficient subjects had to stop exercising due to early muscle fatigue; however, three of the MAD-deficient subjects were able to complete the 20-min exercise test. In conclusion, although the capacity for repetitive submaximal isometric muscle contractions for the group of MAD-deficient subjects was significantly decreased, it remains uncertain whether MAD deficiency is the sole cause of pronounced muscle fatigue.