Document Type : Original Article


Environmental and Occupational Hazards Control Research Center, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran


INTRODUCTION: Aging and chronic diseases associated with nutrition are increasing in the world;
therefore, access to a tool for assessing nutritional literacy in the elderly is necessary. Therefore,
the present study was carried out with the aim of psychometric evaluation of nutritional literacy in
the elderly.
MATERIALS AND METHODS: This study was carried out to psychometric testing of the Nutrition
Literacy Scale (NLS), through the validity and reliability of the tool in 280 elderly people (60 years of
age and older) in Tehran. The validity of this tool was determined through the methods of translation,
face and content and reliability of the tool through the methods of test–retest and internal consistency.
Finally, the tool was analyzed using SPSS software version 16.
RESULTS: In this study, content validity index (CVI) was calculated for each item; CVI average
was 0.86.5. To determine the reliability of the tool, interclass correlation coefficient was calculated
by measuring the instrument’s stability, and it was 0.92. Exploratory factor analysis confirmed the
existence of six factors in the questionnaire, which was named nutritional information, healthy
nutrition, calorie intake, organic foods, saturated fats, and unit size, which explains 43% of the total
variance. Furthermore, in the internal consistency assessment, the questionnaire was completed
by 280 elderly people, and the Cronbach’s α coefficient was 0.80.
CONCLUSION: Based on the results obtained in the reliability and validity assessment, NLS in
Iranian elderly has a desirable reliability and validity. This questionnaire has been translated into
Persian for the first time. The results of this study provide a standard tool for assessing nutritional
literacy status in Persian language communities.


1. World Health Organization. Ageing. Available from: http:// [Last accessed on 2017 Apr20].
2. World Health Organization. Ageing and Health. Available from: [Last
accessed on 2017 Apr17].
3. United Nations. World Population Ageing: 1950‑2050. Available
worldageing19502050. [Last accessed on 2017 Apr20].
4. World Health Organization. Noncommunicable Diseases
Country Profiles; 2014. Available from:
nmh/publications/ncd‑profiles‑2014/en. [Last accessed on
2017 Apr28].
5. Barry MM, D’Eath M, Sixsmith J. Interventions for improving
population health literacy: Insights from a rapid review of the
evidence. J Health Commun 2013; 18:1507‑22.
6. Inoue M, Takahashi M, KaiI. Impact of communicative and critical
health literacy on understanding of diabetes care and self‑efficacy
in diabetes management: A cross‑sectional study of primary care
in Japan. BMC Fam Pract 2013; 14:40.
7. Ford ES, Bergmann MM, Kröger J, Schienkiewitz A, Weikert C,
Boeing H. Healthy living is the best revenge: Findings from
the european prospective investigation into cancer and
nutrition‑potsdam study. Arch Intern Med 2009; 169:1355‑62.
8. Eyles HC, Mhurchu CN. Does tailoring make a difference? A
systematic review of the long‑term effectiveness of tailored
nutrition education for adults. Nutr Rev 2009; 67:464‑80.
9. Knoops KT, de Groot LC, Kromhout D, Perrin AE,
Moreiras‑Varela O, Menotti A, et al. Mediterranean diet, lifestyle
factors, and 10‑year mortality in elderly european men and
women: The HALE project. JAMA 2004; 292:1433‑9.
10. Silk KJ, Sherry J, Winn B, Keesecker N, Horodynski MA, Sayir A.
Increasing nutrition literacy: Testing the effectiveness of print,
web site, and game modalities. J Nutr Educ Behav 2008; 40:3‑10.
11. Carbone ET, Zoellner JM. Nutrition and health literacy:
A systematic review to inform nutrition research and practice.
J Acad Nutr Diet 2012; 112:254‑65.
12. Guttersrud O, Dalane JØ, Pettersen S. Improving measurement
in nutrition literacy research using rasch modelling: Examining
construct validity of stage‑specific ‘critical nutrition literacy’
scales. Public Health Nutr 2014; 17:877‑83.
13. Vaitkeviciute R, Ball LE, Harris N. The relationship between food
literacy and dietary intake in adolescents: A systematic review.
Public Health Nutr 2015; 18:649‑58.
14. Aihara Y, Minai J. Barriers and catalysts of nutrition literacy
among elderly japanese people. Health Promot Int 2011; 26:421‑31.
15. Zoellner J, Connell C, Bounds W, Crook L, Yadrick K. Nutrition literacy status and preferred nutrition communication channels
among adults in the lower mississippi delta. Prev Chronic Dis
2009; 6:A128.
16. Diamond JJ. Development of a reliable and construct valid
measure of nutritional literacy in adults. Nutr J 2007;6:5.
17. Plichta SB, Kelvin EA, Munro BH. Munro’s Statistical Methods
for Health Care Research. Canada: Wolters Kluwer Health/
Lippincott Williams and Wilkins; 2012.
18. Patel P, Panaich S, Steinberg J, Zalawadiya S, Kumar A, Aranha A,
et al. Use of nutrition literacy scale in elderly minority population.
J Nutr Health Aging 2013; 17:894‑7.
19. Taylor WL. Cloze procedure: A new tool for measuring
readability. Journal Bull 1953; 30:415‑33.
20. World Health Organization. Process of Translation and
Adaptation of Instruments. Available from: https://www.who.
int/substance_abuse/research./translation/en. [Last accessed
on 2018 Nov8].
21. Lawshe CH. A quantitative approach to content validity 1. Pers
Psychol 1975;28:563‑75.
22. Yaghmale F. Content validity and its estimation. J Med Educ 2003;
23. Bryman A, Cramer D. Quantitative data analysis with SPSS release
10 for Windows: A guide for social scientists. USA and Canada:
Routledge: 2002
24. Cook DA, Beckman TJ. Current concepts in validity and reliability
for psychometric instruments: Theory and application. Am J Med
2006; 119:166.e7‑16.
25. Drost EA. Validity and reliability in social science research. Educ
Res Perspect 2011; 38:105.
26. Polit DF, Beck CT. The content validity index: Are you sure you
know what’s being reported? Critique and recommendations.
Res Nurs Health 2006; 29:489‑97.
27. Cohen L, Manion L, Morrison K. Research Methods in Education.
USA: Routledge; 2013.
28. Munro BH. Statistical Methods for Health Care Research.
Philadelphia: Lippincott Williams and Wilkins; 2005. p. 105.
Available from: &lr=&
cal+Methods+for+Health+ Care+Research.+Philadelphia. [Last
accessed on 2017 Nov 9].
29. Pintrich PR, Smith DA, Garcia T, McKeachie WJ. Reliability
and predictive validity of the motivated strategies for learning
questionnaire (MSLQ). Educ Psychol Meas 1993; 53:801‑13.
30. Hayton JC, Allen DG, Scarpello V. Factor retention decisions in
exploratory factor analysis: A tutorial on parallel analysis. Organ
Res Methods 2004; 7:191‑205.
31. Khaghanizade MP, Ebadi A. Review of translation and cultural
adaptation process of questionnaires. Educ Strategies Med Sci
2009; 2:117‑20.
32. Plichta SB, Kelvin EA, Munro BH. Munro’s Statistical Methods
for Health Care Research. Canada: Wolters Kluwer Health/
Lippincott Williams and Wilkins; 2013. p. 14‑34.
33. DeVon HA, Block ME, Moyle‑Wright P, Ernst DM, Hayden SJ,
Lazzara DJ, et al. A psychometric toolbox for testing validity and
reliability. J Nurs Scholarsh 2007; 39:155‑64.
34. Webb NM, Shavelson RJ, Haertel EH. 4 Reliability Coefficients
and Generalizability Theory. Handb Stat 2006; 26:81‑124.
35. Walter SD, Eliasziw M, Donner A. Sample size and optimal
designs for reliability studies. Stat Med 1998; 17:101‑10.
36. Gliem JA, Gliem RR, editors. Calculating, Interpreting,
and Reporting Cronbach’s Alpha Reliability Coefficient for
Likert‑type Scales; 2003: Midwest Research‑to‑Practice Conference
in Adult, Continuing, and Community Education. Available from:[Last accessed on 2017 Nov 11].
37. Johnson R, Wichern D. Applied Multivariate Statistical Analysis.
Upper Saddle River, New Jersey: Prentice Hall, NJ; 1998.