Thursday, September 2, 2010

Should we tell Nagas to stop eating smoked meat?

Nagaland has the highest incidence rate of nasopharyngeal carcinoma (NPC) in India. Though mouth cancers are common in India, NPC is rare except among the specific ethnic groups like the Nagas. The incidence rate of 4.3 per 1, 00,000 population in Nagaland falls under the intermediate category while the highest incidence rates are found in southern China (10-20 in males and 5-10 in females). In most parts of the world, the incidence is less than 1 per 1, 00,000 population. Though this is a serious health concern for the Nagas, it doesn’t get sufficient attention in the national scene, similar to its political struggle. There has been a lot of research done in China and South East Asia but Nagaland gets mentioned only on a passing note. As far as I know, apart from hospital statistics, there are only two researches done in Nagaland (One by P.K Chelleng et al, titled 'Risk factors for cancer Nasopharynx: A case-control study from Nagaland, India'; published in National Medical Journal of India, 2000, 13:6-8; and the other published in Carcinogenesis Journal 1989 OUP, ‘Mutanegecity and Carcinogenicity of smoked meat from Nagaland, a region of India prone to high prevalence of Nasopharyngeal cancer’, conducted by S. Sarkar et al from the cancer research institute, Tata Memorial Hospital, Mumbai). S. Kumar, et al has a study of NPC with reference to the North Eastern Region of India. In Nagaland, consumption of smoked meat has been linked to high prevalence of NPC. In the second study mentioned above, the charred portion of smoked beef and meat of other animals were collected and tested. It was found to be mutagenic to the Amas test, clastogenic in a mammalian test system and has the potential to induce skin papilloma in mice.
There are other risk factors associated with NPC and it is difficult to estimate which factor contributes more and which less. Epidemiology of NPC has earned the titles ‘confusing’, 'enigmatic' or 'intriguing' because of the interplay of environmental, viral and genetic risk factors. The ICMR bulletin reports that the disease is ‘one of the most confusing, commonly misdiagnosed, and poorly understood diseases’. NPC is not a common cancer in the world or India, but it is a leading form of cancer in a few well defined ethnic/racial groups in particular geographical locations. This gives important clues to explain the risk factors. The cancer is common in southern China and South-East Asia and this may explain the racial and cultural similarities between the people of South China/Hongkong and Nagas. Epstein Barr virus has also been closely associated with NPC. This trinity of genetic susceptibility, EB virus infection, and smoked meat in Nagaland (salted fish in South China) is linked to be causal factor for NPC. In the first study (case-control) done in 47 known cases in Nagaland, smoked meat and use of herbal nasal medicine were found to be risk factors for NPC. However, exposure to a smoky atmosphere, betel-nut chewing, use of smokeless tobacco products, smoking and drinking habits were not found to be associated with NPC. Nagas have the cultural practice of putting other food items over the fire place, e.g. fermented soya bean, garlic, chilli, etc. These were not taken into consideration. Villagers spend most of the time at home in the kitchen which does not have a proper chimney and therefore inhale excess of smoke. Although the research found no co-relation, there are studies done in other places which showed significant associations. Nothing can be done about genetic susceptibility, at least for now. So, should the Nagas give up smoked meat? I think the answer is not a simple yes. Let’s take the example of alcoholism: the favorite sin of Naga men which stimulates selective, extraordinary anger among church leaders. Simplistic measures, for example, behavioral change of deciding to give up alcohol may work in the individual but that alone cannot control the problem of alcoholism in the society. There are larger societal factors like law, religion, family structure, availability and price of alcohol, income, peer pressure, political situation, etc in play. The problem is no less in case of NPC when the risk factor is a traditional food item deeply entrenched in cultural history and is hardly seen as a problem at all. An alternative method of drying meat without smoking is being tried which is a positive move. I do not have slick solutions other than spreading this awareness and proposing for further studies. The disease incidence can be an underestimation as villagers may not report early (or at all) for painless neck swelling or they may be financially too poor to go to the town/city for medical treatment. Except for the dietary habit and genetic predisposition, we cannot assume similarity in socioeconomic conditions between Nagaland and Southern China which has a bearing on disease occurrence, characteristics and outcomes. Treatment seeking behavior, availability and accessibility of health facilities in Nagaland, treatment cost (e. g. at RIMS Imphal, CMC Vellore, Tata Memorial Mumbai, AIIMS Delhi, etc); burden of suffering, economic impact/indebtedness because of receiving treatment outside state, outcomes, and duration of survival are some of the areas needing further research. Such studies will show a bigger picture of how serious and how big is the problem of NPC in Nagaland.