The study is a community based cross-sectional study conducted among women residing in the field practice area of Urban Health Training Centre, Dukli under Department of Community Medicine, Tripura Medical College and Dr BRAM Teaching Hospital, for a period of three months (November 2017 to January 2018). A minimum sample size of 260 was calculated considering prevalence (p) as 82.4% as per DLHS-4 report of urban Tripura [12] and allowable error (l) as 5% using the formula of n=4 pq/l², where n is total sample size and q=1-p. This gives a minimum sample size of 232. Finally, considering 10% as non-response rate, 260 individuals were selected from a peri-urban area for the purpose of this study.

Study individuals were selected by simple random sampling technique, where 260 individuals from the field practice area of UHTC Dukli were selected by using computer generated random number table starting from one fixed point. Household numbers from routine field survey of UHTC were used for random sampling. If women were not found or absent in the house during survey, the next household as per random number table was visited until the required sample size was achieved.

Women who were involved in cooking daily household meals and gave their consent to participate were included in the study. If more than one person from target population were found in the same household, the one with less experience in daily cooking was excluded from the study. Also, those who were not mentally healthy were not included. A pre-designed, semi-structured, pre-tested interview schedule was developed by the investigators to collect the required information from the study participants. The interview schedule consisted of two parts; in the first part the investigators asked questions (eight in number) related to socio-demographic characteristics of the respondents and second part of the schedule involved six questions related to knowledge, three questions of attitude and five questions to find out practice of consumption of iodized salt at household level. The interpretation of the questions has been mentioned. The schedule was translated into local language (Bengali) by experts in literature for appropriateness and comprehension. The schedule was pre-tested in a separate urban female population of the same city, by the investigators before commencing the original research work and Cronbach’s alpha calculated to be 0.69, which means good reliability.

The collected data were entered in SPSS version 16.0 computers based software and represented in proportions with the help of frequency distribution tables and charts. Chi-Square Test and Fisher’s-exact test were used to see the association between socio-demographic factors with the knowledge, attitude and practice of the study participants (p<0.05 was used as significant).

A well explained written informed consent, translated into local language (Bengali) was taken from all the study participants before interview.

Study proposal was submitted in front of the Institutional Ethics Committee of Tripura Medical College and Dr BRAM Teaching Hospital (Ref. Sl. IEC/SFTMC/2017/5/002, Dated: 15/09/2017) and ethical clearance was taken before commencing the study.

The present study revealed mean age of participants as 36.89±12.001 years and nearly similar proportion of participants being above mean {115 (44.2%)} and below or equal to mean {145 (55.8%)}. All the study participants were Hindu by religion and General caste {124 (47.7%)} followed by ST {86 (33.1%)}. Most of them were married, housewives and had high school education. Majority belonged to nuclear families and from SES Class IV followed by SES Class III as per modified BG Prasad’s SES Classification, January 2017 [Table/Fig-1] [13].

In this study majority {168 (64.62%)} of the participants haven’t heard of iodized salt and among the rest 80 (86.96%) believed its common salt with iodine rather than any special salt. Only 31 (11.9%) participants were aware that the salt they consume at their home was having iodine and only 52 (20%) knew that iodized salt doesn’t taste any different than table salt. Only 19 (7.3%) participants knew how to identify iodized salt from the packet. Although almost all {258 (99.2%)} preferred packaged salt than unpackaged open salt and for majority {96 (36.9%)}, taste was the main reason for their salt preference. Still majority believed that iodized salt was somewhat important {118 (45.4%)} followed by very important {91 (35%)} in their diet for maintaining good health. When interviewed about their practices, almost all of them {258 (99.2%)} replied that they were using packaged salt and only 2 (0.8%) were using coarse salt. Most of them {243 (93.5%)} were avoiding direct exposure of edible salt to sunlight and storing salt in dry area {254 (99.7%)}. Most of them were using covered container for salt. Majority said that they used to add salt either in the middle of cooking {161 (61.9%)} or at the beginning {95 (36.5%)} but only 4 (1.5%) added salt at the end of cooking [Table/Fig-2].

[Table/Fig-3] revealed good knowledge and good practice among majority {146 (56.2%) and 227 (87.3%) respectively} of the participants regarding iodized salt consumption but poor attitude among 152 (58.5%) of the individuals.

Mean age, social caste, education, occupation and socio-economic class of the individuals were found to have significant association with their knowledge of iodized salt consumption (p-value=0.008, <0.001, <0.001, 0.002, 0.025 respectively). Similarly mean age, education and SES class had significant association with attitude of iodized salt consumption (p-value=0.026, <0.001, 0.009 respectively) [Table/Fig-4].

The present study revealed mean age of participants as 36.89±12.001 years and majority (55.8%) were aged less than 37 years. As per modified BG Prasad’s SES Classification, January 2017, majority belonged to Class IV (lower middle socio-economic class). They had similarity in baseline characteristics to various other studies included in discussion [14-25].

While assessing knowledge of the study participants regarding consumption of iodized salt it was found in this study that only 35.38% of the participants have heard of iodized salt. Similar results were found in a study done by salt commission in 2010 in eight states [14] and study by Sen TK et al., West Bengal, where they have found that 57.8% and 60% of their study population have never heard of iodized salt [15]. Although there was lot of dissimilarities in various other studies regarding the same e.g., like study done in Chennai by Cariappa MP et al., where 79.6% population knew about iodized salt, only 30.6% in a study at Bangalore by Jaiswal N et al., 72% of the population in study done by Kumar P et al., and among studies done in other countries, 36.7% of the population in study done by Sarah NA et al., in Ghana, 85.3% in study at Sindh and provinces of Pakistan by GN Khan et al., 69.3% of urban population of study done by Tsegaye M et al., in Southern Ethiopia [16-21]. This difference in knowledge could probably be because of difference in population distribution, their education and salt consumption pattern.

In this study, 11.9% of the study participants were aware that the salt they consume at their homes were having iodine which is quite less than that of study results by Roy R et al., in Uttar Pradesh, where 90.9% of the study population knew that packaged salt contains iodine [22]. This is a matter of serious concern regarding knowledge of our study population. Similarly the proportion of our study population having knowledge on identifying iodized salt packet by ‘smiling sun’ logo was also very poor (7.3%) consistent to findings in various other studies, 12.2% in study done by Cariappa MP et al., in Chennai and only 4% in study done by Kumar P et al., [16,18].

While various other studies reported majority of their study population were unaware of the importance of iodized salt (63.4% in study by Sen TK et al., in West Bengal and 53.8% in the study by Roy R et al., [15,22]. Most of our study population (80.4%) opined that iodized salt was important in their daily food.

Although most of our study population were using packaged salt, avoiding direct sun exposure to salt, keeping salt in dry place and in covered container but only 1.5% were using salt at the end of cooking, whereas, it was 8.16% in the study at Chennai [16], 7.1% in study at Bangalore [17] but comparatively lesser than study at Ethiopia where 50.2% of study population used salt at the end of cooking [23].

Majority of the participants in the present study showed good knowledge and practice regarding iodized salt consumption, better than what Aruna RT et al., found in their study in Karnataka [24].

The present study revealed that higher age, improved literacy status and higher socio-economic class were the factors that were significantly associated with good knowledge and attitude of the participants which is consistent with study findings by salt commission in eight states of India and Singh S et al., in Kanpur [14,25]. This might be because higher education and income allowed people to understand and act upon information regarding iodized salt consumption at their household level.

Lack of availability of a standard questionnaire format and subjective nature of responses, especially lack of objective assessment of practice of iodized salt consumption by the participants could be the possible limitations of the study.

The study revealed good knowledge and practices regarding consumption of iodized salt among urban women involved in household cooking in Tripura, even though majority of them haven’t heard of iodized salt. Also, adding salt at the end of cooking to avoid loss of iodine content in salt was not among their common practices, consistent with other parts of our country. A positive change in the attitude and above mentioned practice might help in reducing the burden of IDD in our country which is a scope for future research work in this context.

Ethical Approval: The study was approved by the Institutional Ethics Committee (Tripura Medical College and Dr BRAM Teaching Hospital, Agartala).