|LETTER TO THE EDITOR
|Year : 2021 | Volume
| Issue : 4 | Page : 781-782
Authors' reply to Tripathi et al., Majumdar and Mirnezami
Tasneef Zargar1, Dinesh Kumar2, Bhavna Sahni1
1 Department of Community Medicine, Govt. Medical College (GMC), Doda, Jammu and Kashmir, India
2 Department of Social and Preventive Medicine, Govt. Medical College (GMC), Doda, Jammu and Kashmir, India
|Date of Submission||23-Nov-2021|
|Date of Decision||24-Nov-2021|
|Date of Acceptance||02-Dec-2021|
|Date of Web Publication||29-Dec-2021|
Department of Community Medicine, GMC Jammu, Jammu, Union Territory of J&K
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Zargar T, Kumar D, Sahni B. Authors' reply to Tripathi et al., Majumdar and Mirnezami. Cancer Res Stat Treat 2021;4:781-2
We thank Tripathi et al., Majumdar, and Mirnezami for critically appraising our article titled, “Dietary risk factors for colorectal cancer: A hospital-based case–control study.”,,, It is true that estimation of disease burden is indeed the first step in controlling any public health issue. Statistics of colon cancer from the hospital-based cancer registry (HBCR) in Government Medical College Jammu for the period during which the study was conducted reveal that colon cancers comprised 4.2% of the total cancers registered at the HBCR.
Although measurements of body mass index (BMI) were made for both cases and controls, we did not report this in the article as BMI at the time of cancer diagnosis is always low, especially in patients with colon cancer, and we did not have baseline data for most of the patients. Therefore, we excluded this parameter to avoid measurement and misclassification bias.
We acknowledge that the observed associations of diet with cancer risk can be confounded by factors like physical activity. Moreover, physical activity questionnaires, generally do not measure physical activity with a high degree of accuracy and there has been a heightened appreciation for the error associated with assessing physical activity in recent years. Investigators now use more objective tools such as heart rate monitors, accelerometers, or combinations to measure physical activity. However, this kind of assessment was beyond our capacity as investigators.
The confounding effect of one or more unknown or inadequately measured exposures can result in modest associations (1.5–2.0 or even less). In this context, the cancer risk observed for consumption of hot tea (odds ratio, 1.81; confidence interval [0.99–3.31]) could be due to confounding with the association just reaching significance (the actual P value was 0.0497), which did not inspire much confidence in the observed findings. We are collecting more data to be able to perform a multivariate analysis, but until then, we believe that these crude estimates should be considered exploratory in nature.
Alcohol consumption was equally prevalent in cases (55%) and hospital controls (58%), but as expected, neither the odds nor the association was significant. Alcohol was reported to increase the odds of colon cancer by 2.6 times only when male patients were compared to healthy controls (32%).
As for pickling, methods of preservation like salting, smoking, and the addition of chemical preservatives are known to generate carcinogens. Salt-preserved foods and high salt intake increase the risk for stomach cancer, which could be the underlying mechanism for colon cancer as well.
Intake of dietary fiber is extremely difficult to quantify, although we agree that the intake of junk food could have been studied.
As far as consumption of red meat is concerned, restricting protein intake after the diagnosis of cancer is open to debate. Although there are clear recommendations for the amount of red meat (350–500 g cooked weight per week) that may be consumed, simply removing red meat from the diet may compromise nutritional adequacy, as it can be a valuable source of nutrients such as protein, iron, zinc, and Vitamin B12. Hence, the recommendation is not to completely avoid eating red meat but to avoid eating processed meat. However, eating meat is not an essential part of a healthy diet and people who choose to eat meat-free diets can obtain these nutrients through careful food selection.
We agree with the concerns of recall bias, which we have already acknowledged as a limitation, and increased participation of health-conscious individuals as controls. This was precisely the reason that two groups of controls were included in the study. The inclusion of hospital controls may to an extent have minimized any participation bias.
Socioeconomic status and literacy rates are inter-related and were considered by default, as most public health facilities in India, like ours, cater mainly to patients belonging to lower and middle socioeconomic classes, which also constitute a major chunk of the general population.
Members of a family may share similar food habits, and this was the exact reason that the methodology was flexible in including not only siblings but also friends, neighbors, or healthy attendants of other patients to minimize bias. Healthy controls did not undergo colonoscopy or sigmoidoscopy before inclusion, as in our experience, interventional procedures such as these, in the absence of health issues, have very low acceptance.
We agree that methods of cultivation, preparation, packaging, storage, and cooking are likely to affect cancer causation, and such studies would not only reinforce the credibility of the initial food frequency questionnaire (FFQ) based-findings but would also advance our understanding of nutrition and carcinogenesis.
Precision nutrition is the long-term goal, but India, as of today is not ready for widespread precision nutrition strategies, as malnutrition is in itself a major public health problem in India, and the pros and cons need to be weighed, as many of the patients with cancer are financially exhausted and cachexic.
In most cases, the purpose of an FFQ is to obtain only a crude estimate of the usual dietary intake over a designated period. We agree that further studies about the knowledge, attitude, and practices among patients and physicians will help us assess eating behaviors and the desired change in practice. Until then, we can keep praying, eating, exploring, and sharing our results with each other!
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Tripathi M, Pandey D, Chopra S. Diet and colorectal cancers. Cancer Res Stat Treat 2021;4:778-9. [Full text]
Majumdar S. Diet and colorectal cancer: Eat, pray, and live with the consequences. Cancer Res Stat Treat 2021;4:779-80. [Full text]
Mirnezami R. Toward precision nutrition in the fight against colorectal cancer. Cancer Res Stat Treat 2021;4:777-8. [Full text]
Zargar T, Kumar D, Sahni B, Shoket N, Bala K, Angurana S. Dietary risk factors for colorectal cancer: A hospital-based case – Control study. Cancer Res Stat Treat 2021;4:479-85. [Full text]
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