A mini review:
Indicator of higher cancer risk--Increased BMI or Excess hidden visceral
Prof (Dr) Jogenananda Pramanik.MD Professor & Head of
Biochemistry & Genetics,
and Director of International Relations, Allianze College of Medical
Sciences, Penang-13200,Malaysia. www.acms.edu.my E-mail:
Reeves GK and his colleagues, once again made it clear to all of us
that higher body mass index (BMI) is significantly associated with an
increased risk of fatal cancers (1) which has been described earlier by
several other researchers (2).
In recent years, the body mass index (BMI) is popularly used to gauge
the obesity. However, there is a growing body of literature emerging with
a different picture which cannot be ignored.
In the recent past, a number of researchers described that one can
have normal BMI and yet carry unseen excess fat causing masked obesity
which is not at all free from fatal cancer risk. Earlier Jennifer J.
Griggs et al, argued that the definition of obesity itself is
controversial. It is unclear whether BMI is the most appropriate measure
of obesity.BMI makes no distinction between body weight from muscle and
body weight from fat (3). Muscular individuals i.e Sumo wrestlers in
Japan, can be categorized as overweight or obese when obviously they are
not. In 1953, the average weight of a sumo wrestler was 317 pounds, while
the average height was 5-foot 11, according to the sumo association.
Today, the average wrestler is just 3.2 inches taller, but 95 pounds
In a current study, T.Ohki et al (2009), revealed that in contrast to
BMI, visceral fat accumulation is considered to be directly causative of
non-B and non-C hepatocarcinogenesis, through disturbing the adipocytokine
balance of insulin resistance, which is a major cause of hepatic fat
accumulation. Excessive fat in the liver will lead to hepatocellular
injury and possibly result in hepatocarcinogenesis through the direct
cellular toxicity of excessive free fatty acids, oxidant stress and lipid
peroxidation, or some other mechanism. Visceral fat accumulation may be
involved in both tumor initiation and promotion or progression steps
through these mechanisms (4).
Therefore, it is not at all surprising that preoccupation with body
weight, fitness, and diet is spreading exponentially all over the world.
Interest in physical activity, at least as evidenced by scores of joggers,
in-line skaters, bicyclists, and walkers, seems to be increasing in Asian
countries as well. Health clubs and fitness centers have proliferated, and
home exercise equipments are readily available everywhere at a reasonable
Moreover, Wandy Y Chen (2008) mentioned in his commentary that there is a
weakness in the current study of Reeves GK et al. because this study was
conducted within short follow-up time, especially for cancer mortality. He
also mentioned about a general methodological concern in this study
protocol regarding studies linking BMI and mortality. That is, people may
lose weight for a period of time before the actual diagnosis of cancer (or
death from cancer in mortality analysis) and, therefore, lower BMI may be
associated with worse cancer incidence and mortality when actually it is
the cancer that is causing the BMI change and not vice versa.(5)
Despite existing challenges and limitations in our knowledge base
regarding altered responses of our own body system and resultant impact on
cancer genes, we need to continue to examine the relationship between
obesity and cancer.
We concluded that the current study provided renewed impetus to health
care providers to counsel patients regarding the importance of maintaining
a healthy body weight.
1 Reeves GK, Pirie J, Beral V, Green J, Spencer E, Bull E. Cancer
incidence and mortality in relation to body mass index in the Million
Women Study: cohort study BMJ, Nov 2007; doi:10.1136/bmj.39367.495995.AE.
2. Calle EE, Rodriguez C, Walker-Thurmond K, et al: Overweight,
obesity, and mortality from cancer in a prospectively studied cohort of
U.S. adults. N Engl J Med 348:1625-1638, 2003.
3. Jennifer J. Griggs, Michael S. Sabel: Editorial: Obesity and cancer
treatment: Weighing the evidence: Journal of Clinical Oncology, Vol 26, No
25 (September 1), 2008: pp. 4060-4062
4.T.ohki, R Tateisi, S Shina et al,: Visceral fat accumulation is an
independent risk factor for hepatocellular carcinoma recurrence after
curative treatment in patients with suspected NASH: Gut 2009;58:839-844
5. Wendy Y. Chen: Million Women Study: Higher BMI Increases Cancer
Incidence and Mortality (2008)