Meta-analysis

In chapter 2 we introduce meta-analysis, a statistical procedure for examining the results of a large number of similar studies.

A large meta-analytic study was recently released by the World Cancer Research Fund. That study found links between body fat and six types of cancer. They are: cancer of the esophagus, the pancreas, the colon, the womb, the kidney, and the breast (post-menopause).

The study looked some 7,000 published research reports published since the 1960s (out of a possible half-million articles). Dr. Michael Marmot, an epidemiologist, directed the project.

The report recommends:

• ham, bacon, and other processed meats should be eaten rarely
  
• no more than a pound of cooked red meat should be eaten weekly
• drinking no more than a small glass of wine (or equivalent) per day
• mothers should breastfeed for at least six months because that lowers their incidence of breast cancer
• exercising at least 30 minutes per day and working up to 60 minutes per day
  
• minimizing salt use
• drinking water instead of drinks with sugar
• eating fruit, vegetables and fiber

Meta-analytic studies strive to see the "big picture" created by many smaller and narrower empirical studies. To see the full report from the World Cancer Research Fund click here.