1. Introduction
Currently, improving lifestyles, promoting health, and advancing medical knowledge have increased the life expectancy of the elderly in communities [1]. Older adults, particularly those living in nursing homes, are a vulnerable group whose poor nutritional status and inadequate nutrient intake provide the basis for the incidence of diseases and increase their health costs [4, 5]. There are different dietary indicators to assess the quality of diets. One of the most critical and new indicators of dietary health is the Index of Nutritional Quality (INQ). The INQ for each nutrient is calculated as the ratio of its daily consumption per 1000 kcal to its Recommended Dietary Allowances (RDA) per 1000 kcal [6].
The association of INQ with some chronic diseases such as multiple sclerosis syndrome, breast cancer, ulcerative colitis, and fatty liver has been investigated [14, 15, 16, 17]; however, its association with the inflammatory status in older adults is unclear. Therefore, the present study aimed to compare the Index for Nutritional Quality (INQ) between institutionalized (nursing-home) and non-institutionalized (community-living) older adults. We also aimed to investigate its association with serum high sensitive C-reactive protein (hs-CRP) level per group. 
2. Materials & Methods
In this case-control, age- and gender-matched study in Tabriz City, Iran, the eligible old people aged 65 years and older were recruited from nursing homes and communities. The exclusion criteria were smoking, alcohol consumption, severe physical or mental illness, liver and kidney disease, chronic inflammatory disease, cold or acute infection during the last two weeks. An informed written consent form was obtained from the eligible participants, and a trained questioner completed the other relevant questionnaires.   
Anthropometric parameters (height & weight) were measured using the calibrated equipment, and Body Mass Index (BMI) was calculated. A three-day record of the nursing home residents’ foods was weighed using a digital scale. The whole food intake of older adults was converted to grams, and dietary data were analyzed using Nutritionist IV. The INQ for each nutrient was calculated according to the formula mentioned above. Individuals with an average daily energy intake below 800 kcal or more than 4200 kcal were excluded from the study. A fasting blood sample was drawn to measure serum hs-CRP level using the ELISA method. SPSS was used for data analysis. The significance level was set at P<0.05.
3. Results
In the present study, eligible older adults from the residents of nursing homes (n=76) and the community-living older adults (n=88) were recruited. The Mean±SD age of the residents of the nursing homes was 74.7±7.9 years. Moreover, the Mean±SD age of the community-living older adults was 72.6±7.7 years. As per Table 1, INQ for all nutrients (except for vitamins A, D, E, biotin, vitamin B6, folic acid, and iron) was significantly different between the two groups (P<0.05).


The INQ<1 for these nutrients (except for iron) in both study groups indicated insufficient intake of these micronutrients. However, INQ for nearly all nutrients (other than selenium) was higher in the community-living older adults compared to nursing-home residents (P<0.05). The intake of minerals, including calcium, magnesium, manganese, selenium, zinc, chromium, sodium, and potassium, was insufficient in both groups. Nursing-home residents did not meet their estimated vitamins B2, B12, and copper needs. 
The median and Interquartile Range (IQR) for serum hs-CRP in the residents of the nursing homes were 7.29 (2.03 and 20.62) mg/L, and in the community-living older adults were 5.24 (2.46 & 11.69) mg/L. There was no statistically significant difference between the two groups (P=0.145). A significant reverse association was observed for serum hs-CRP level and INQ for vitamin D (P=0.04) and calcium (P=0.038) in the community-living older adults after adjusting for BMI (Table 2).


A correlation was also reported between INQ for vitamin B12 and serum hs-CRP level in both research groups (P=0.02).
4. Discussion & Conclusion
To the best of our knowledge, this is the first study in which the adequacy of nutrient intake in older adults was assessed through INQ. According to our findings, old people, especially those living in nursing homes, do not receive the recommended nutrients. According to the INQ, there was a significant difference between community-living older adults and the elderly living in nursing homes. These results are consistent with some previous studies. For example, a study conducted on 200 elderly living in the nursing home in Markazi Province [20] reported that 19.6% of participants had malnutrition, 53.3% were at risk of malnutrition, and only 27.1% had good nutrition. Similarly, Saghafi and Vaghef [7] revealed that 53.3% of elderly people in Tabriz were at risk of malnutrition, and 2.7% were malnourished. According to the results of a review study [5], the prevalence of malnutrition in the Iranian elderly is high (12.2%). The prevalence of malnutrition was higher in those living in nursing homes than community-living older adults. A study in Turkey also reported that the intake of nutrients in the elderly living in nursing homes was less than the recommended amounts [21].
In the present study, there was a reverse correlation between INQ for dietary calcium intake and serum hs-CRP levels, i.e., consistent with the results of Katsuura-Kamano et al. [25]. Moreover, our results suggested a significant reverse correlation between INQ for dietary vitamin B12 intake and serum hs-CRP after adjustment for BMI. In conclusion, it is recommended to pay more attention to the nutritional status of older adults, especially those living in nursing homes. It seems that a diet rich in micronutrients, especially vitamin D, calcium, and vitamin B12, may help prevent the development of inflammation in the aged population.

Ethical Considerations
Compliance with ethical guidelines
The present research was approved by Tabriz University of Medical Sciences (Code: TBZMED.REC.1394.152). All subjects were informed about the study and signed a written informed consent form.

Funding
The present study was conducted with the financial support of the Nutrition Sciences Research Center of Tabriz University of Medical Sciences. 

Authors' contributions
All authors met the standard writing criteria based on the recommendations of the International Committee of Medical Journal Publishers (ICMJE) and were equally involved in designing and writing the article as follows: Design and conceptualization: Maryam Saghafi Asl and Vahideh Ebrahimzadeh Attari; Research and sampling method: Maryam Saghafi Asl, Vahideh Ebrahimzadeh Attari and Azimeh Izadi; Data analysis and interpretation: Azimeh Izadi; Text Writing and Review: All Authors. 

Conflicts of interest
The authors declared no conflicts of interest.

Acknowledgements
We wish to express our appreciation to the Nutrition Research Center, Tabriz University of Medical Sciences, for the financial support. We also would like to thank all of the old people who participated in the study.


References

1. Leeson GW. The growth, ageing and urbanisation of our world. J Popul Aging. 2018; 11(2):107-15. [DOI:10.1007/s12062-018-9225-7]
2. Heidari M, Shahbazi S. [Effect of self-care training program on quality of life of elders (Persian)]. Iran J Nurs. 2012; 25(75):1-8. [DOI:10.17485/ijst/2012/v5i10.14]
3. van Bokhorst-de van der Schueren MA, Lonterman-Monasch S, de Vries OJ, Danner SA, Kramer MH, Muller M. Prevalence and determinants for malnutrition in geriatric outpatients. Clin Nutr. 2013; 32(6):1007-11. [DOI:10.1016/j.clnu.2013.05.007] [PMID]
4. Fávaro-Moreira NC, Krausch-Hofmann S, Matthys C, Vereecken C, Vanhauwaert E, Declercq A, et al. Risk factors for malnutrition in older adults: A systematic review of the literature based on longitudinal data. Adv Nutr. 2016; 7(3):507-22. [DOI:10.3945/an.115.011254] [PMID] [PMCID]
5. GORJI HA, Alikhani M, Mohseni M, Moradi-Joo M, Ziaeefar H, Moosavi A. The prevalence of malnutrition in Iranian elderly: A review article. Iran J Public Health. 2017; 46(12):1603-10. [PMCID]
6. Sorenson AW, Wyse BW, Wittwer A, Hansen RG. An Index of Nutritional Quality for a balanced diet. J Am Diet Assoc. 1976; 68(3):236-42. [DOI:10.1016/S0002-8223(21)06349-5]
7. Saghafi-Asl M, Vaghef-Mehrabany E. Comprehensive comparison of malnutrition and its associated factors between nursing home and community dwelling elderly: A case-control study from Northwestern Iran. Clin Nutr ESPEN. 2017; 21:51-8. [DOI:10.1016/j.clnesp.2017.05.005] [PMID]
8. Ahn Y, Lee Y, Park H, Song K. Gender and age group differences in nutrition intake and dietary quality of Korean adults eating alone: Based on Korean National Health and Nutrition Examination Survey Data, 2013-2016. Nutr Res Pract. 2021; 15(1):66-79. [DOI:10.4162/nrp.2021.15.1.66] [PMID] [PMCID]
9. Lee JY, Hyun YS, Kim HS. Nutritional status of Korean elderly with dementia in a long-term care facility in Hongseong. Nutr Res Pract. 2019; 13(1):32-40. [DOI:10.4162/nrp.2019.13.1.32] [PMID] [PMCID]
10. Chung HY, Cesari M, Anton S, Marzetti E, Giovannini S, Seo AY, et al. Molecular inflammation: Underpinnings of aging and age-related diseases. Aging Res Rev. 2009; 8(1):18-30. [DOI:10.1016/j.arr.2008.07.002] [PMID] [PMCID]
11. Sarchahi Z, Kooshki A, Rakhshani M, Tofighiyan T. [The association between macronutrients intake with high sensitivity C-reactive protein (hs-CRP) in elderly of Sabzevar Nursing Homes (a cross-sectional study) (Persian)]. Iran J Nutr Sci Food Technol. 2017; 12(2):1-8. http://nsft.sbmu.ac.ir/article-1-2268-en.html
12. Serino A, Salazar G. Protective role of polyphenols against vascular inflammation, aging and cardiovascular disease. Nutrients. 2019; 11(1):53. [DOI:10.3390/nu11010053] [PMID] [PMCID]
13. Orchard T, Yildiz V, Steck SE, Hébert JR, Ma Y, Cauley JA, et al. Dietary inflammatory index, bone mineral density, and risk of fracture in postmenopausal women: Results from the women’s health initiative. J Bone Miner Res. 2017; 32(5):1136-46. [DOI:10.1002/jbmr.3070] [PMID] [PMCID]
14. Kroushavi M, Behrooz M, Rashidkhani B, Bahadori N, Hekmatdoost A. [Association between index of nutritional quality and multiple sclerosis (Persian)]. J Sch Public Health Inst Public Health Res. 2015; 12(3):53-67. http://sjsph.tums.ac.ir/article-1-5192-en.html
15. Vahid F, Hatami M, Sadeghi M, Ameri F, Faghfoori Z, Davoodi SH. The association between the Index of Nutritional Quality (INQ) and breast cancer and the evaluation of nutrient intake of breast cancer patients: A case-control study. Nutrition. 2018; 45:11-6. [DOI:10.1016/j.nut.2017.06.011] [PMID]
16. Vahid F, Hekmatdoost A, Mirmajidi S, Doaei S, Rahmani D, Faghfoori Z. Association between index of nutritional quality and nonalcoholic fatty liver disease: The role of vitamin D and B group. Am J Med Sci. 2019; 358(3):212-8. [DOI:10.1016/j.amjms.2019.06.008] [PMID]
17. Vahid F, Rashvand S, Sadeghi M, Hekmatdoost A. The association between index of nutritional quality and ulcerative colitis: A case-control study. J Res Med Sci. 2018; 23:67. [DOI:10.4103/jrms.JRMS_555_17] [PMID] [PMCID]
18. Park HS, Park JY, Yu R. Relationship of obesity and visceral adiposity with serum concentrations of CRP, TNF-α and IL-6. Diabetes Res Clin Pract. 2005; 69(1):29-35. [DOI:10.1016/j.diabres.2004.11.007] [PMID]
19. Kord VH, Rahmani J, Fatahi S, Tajik S, SHAB BS. [Relationship between alternative healthy eating index (AHEI-2010) with obesity status, serum level of 25-Hydroxyvitamin D, hs-CRP in the Elderly of Tehran City, (Iran) (Persian)]. Qom Univ Ned Sci. 2018; 12(5):53-61. [DOI:10.29252/qums.12.5.53]
20. Ebrahimi Fakhar MR, Zand S. [Nutritional status and associated factors in elderly residents in nursing homes (Persian)]. J Payesh. 2013; 12(2):143-9. http://payeshjournal.ir/article-1-375-en.html
21. Rakıcıoğlu N, Aksoy B, Tamer F, Yıldız EA, Samur G, Pekcan G, et al. Nutritional status and eating habits of the institutionalised elderly in Turkey: A follow-up study. J Hum Nutr Diet. 2016; 29(2):185-95. [DOI:10.1111/jhn.12320] [PMID]
22. Gerrior SA. The nutrient and anthropometric status of physically active and inactive older adults. J Nutr Educ Behav. 2002; 34(S1):S5-13. [DOI:10.1016/S1499-4046(06)60305-9]
23. Shahar D, Shai I, Vardi H, Fraser D. Dietary intake and eating patterns of elderly people in Israel: Who is at nutritional risk? Euro J Clin Nutr. 2003; 57(1):18-25. [DOI:10.1038/sj.ejcn.1601523] [PMID]
24. Lammes E, Törner A, Akner G. Nutrient density and variation in nutrient intake with changing energy intake in multimorbid nursing home residents. J Hum Nutr Diet. 2009; 22(3):210-8. [DOI:10.1111/j.1365-277X.2008.00925.x] [PMID]
25. Katsuura-Kamano S, Uemura H, Yamaguchi M, Nakamoto M, Bahari T, Miki K, et al. Dietary calcium intake is associated with serum high-sensitivity C-reactive protein level in the general Japanese population. J Clin Biochem Nutr. 2018; 62(1):89-93. [DOI:10.3164/jcbn.17-48] [PMID] [PMCID]
26. Da Silva Ferreira T, Torres MRSG, Sanjuliani AF. Dietary calcium intake is associated with adiposity, metabolic profile, inflammatory state and blood pressure, but not with erythrocyte intracellular calcium and endothelial function in healthy pre-menopausal women. Brit J Nutr. 2013; 110(6):1079-88. [DOI:10.1017/S0007114513000111] [PMID]
27. Chung HY. [Dietary Calcium intake is associated with blood lipid profile, blood pressure, inflammatory state and Insulin resistance in type 2 diabetes patients (Korean)]. Korean J Food Nutr. 2016; 29(2):290-9. [DOI:10.9799/ksfan.2016.29.2.290]
28. Stancliffe RA, Thorpe T, Zemel MB. Dairy attentuates oxidative and inflammatory stress in metabolic syndrome. Am J Clin Nutr. 2011; 94(2):422-30. [DOI:10.3945/ajcn.111.013342] [PMID] [PMCID]
29. Sun X, Zemel MB. Calcium and 1, 25-dihydroxyvitamin D3 regulation of adipokine expression. Obesity. 2007; 15(2):340-8. [DOI:10.1038/oby.2007.540] [PMID]
30. Soares MJ, Pannu PK, Calton EK, Reid CM, Hills AP. Vitamin D status and calcium intake in systemic inflammation, Insulin resistance and the metabolic syndrome: An update on current evidence. Trends Food Sci Technol. 2017; 62:79-90. [DOI:10.1016/j.tifs.2017.01.009]
31. De Groot C, West C, Van Staveren W. Meeting nutrient and energy requirements in old age. Maturitas. 2001; 38(1):75-81. [DOI:10.1016/S0378-5122(00)00193-6]
32. Martín-del-Campo F, Batis-Ruvalcaba C, González-Espinoza L, Rojas-Campos E, Ángel JR, Ruiz N, et al. Dietary micronutrient intake in peritoneal dialysis patients: Relationship with nutrition and inflammation status. Perit Dial Int. 2012; 32(2):183-91. [DOI:10.3747/pdi.2010.00245] [PMID] [PMCID]
33. Abavisani M, Sarchahi Z, Kooshi A, Tofighiyan T, Rakhshani MH. The relationship of micronutrients intake and anthropometric indexes with high-sensitivity C-Reactive protein (hs-CRP) in the elderly living in nursing home, Sabzevar, Iran. Prof RK Sharma. 2018; 12(4):4133. [DOI:10.5958/0973-9130.2018.00211.6]
34. Vakili MA, Forooghan M, Nojomi M, Ghaleh Bandi MF, Khodabandeloo N. [A survey on serum levels of B12, folate, and homocyctein in healthy elderly Tehranis (Persian)]. Razi J Med Sci. 2009; 16(63):189-200. http://rjms.iums.ac.ir/article-1-1260-en.html
35. Hosseinzadeh H, Moallem SA, Moshiri M, Sarnavazi MS, Etemad L. Anti-nociceptive and anti-inflammatory effects of cyanocobalamin (vitamin B12) against acute and chronic pain and inflammation in mice. Arzneimittelforschung. 2012; 62(7):324-9. [DOI:10.1055/s-0032-1311635] [PMID]