Introduction

The food frequency questionnaire (FFQ) is presently the main method of estimating the role of diet in the etiology of chronic diseases. The attractive part of FFQ is based on its low cost and feasibility as compared to other diet assessment scales.[1] There is still some limitation to FFQ, its mainly related to non-discrimination of specific food items from food groups.[2] In addition, the food group list limits its flexibility related to the handwritten food and diet records; like data on cooking procedure get lost and person has to confirm daily portion size with that of listed on the form. Due to this weakness of FFQ, validity and reliability of each questionnaire need to be assessed.[1] Each study design estimate dietary intake based on study aims and objectives, it also differs in study population and accuracy of list of the food groups and dietary data.[3] Although the FFQ has few limitations, it is less expensive method of obtaining information from large population with low compliance from the individual over longer period of time.[3] In dietary evaluation, there is no specific “gold standard” or there is a “benchmark” to ensure the accuracy of the FFQ.[4] Thus the, determining the relative validity of a tool relies on a comparative validation, with a superior and ideally separate technique.[5]

Throughout the world, the number of elderly people is expected to rise and among them tooth loss would be a major oral health problem globally.[6,7] Despite of continuous progress in industrialized countries, edentulousness remains a dominant issue in dental diseases[2] and a large population is projected to be impacted for the near future.[8] In relation to overall well-being, focus has recently been given to oral health. As mastication is the primary function of teeth, their loss may decrease the ability to masticate.[9] The elderly individual with loss of tooth usually wear denture to improve their ability to eat, but they often avoid some types of food due to ill-fitting nature of denture. This ultimately results in lower nutritional status among them. It is critical to consider the changes that have occurred in the elderly because they can affect dietary needs.[6]

About 33% of denture wearers reported that the prosthesis does not fit and not suitable for eating. Compared to those with full dentition, patients with ill-fitting dentures are considered to lack 19 nutrients. Patients with ill-fitting dentures often lack 19 essential nutrients, primarily due to their reduced ability to consume certain hard foods such as meat, vegetables, fruits, and beans. The nutrients commonly lacking include protein, fiber, vitamins (such as Vitamin B12, Vitamin D, and Vitamin C), and minerals (such as calcium, iron, and zinc).[8] The impact of these nutrient deficiencies on health is significant. For elderly patients, deficiencies can exacerbate the risk of chronic diseases, reduce physical and cognitive functions, and impair the overall quality of life. Ensuring a balanced diet and proper denture fitment can help mitigate these risks and improve nutritional intake.[7,9] Researcher have also shown that food intake and nutrients are connected not only with the presence of dentures but also the consistency of the denture fit.[10] The relationships among tooth loss, use of dentures, and nutrition remain controversial. One research did not report any relationships between these variables.[11] However, other research has found that nutritional status is correlated with the use of dentures.[12,13] A variety of methods have frequently been used to determine diet and nutrient intake, but sadly, inappropriate nutritional methodologies have also been used.[8] The aim of this systematic literature review was to describe and assess the quality of studies reporting on use of FFQ as a method for assessing food and nutrient intakes or dietary patterns among denture wearers. This review was unique in its specific focus on denture wearers, unlike previous research which often broadly examined various populations. It distinguishes itself by critically evaluating the quality of research reporting on the use of FFQs to assess nutrient intake in denture wearers, highlighting methodological gaps and suggesting improvements for future studies.

Materials and Methods

Based on the finding of the previous studies, this systematic review was conducted using preferred reporting items for systematic reviews and meta-analyses Statement.[14] This review is not published or registered anywhere because it is an evaluation of the quality of studies carried among the denture wearers and it does not base on a health-related results.

Data extraction

The data mining sheet was made depending on examples found in the literature. Two researchers (RG and HA) separately analyzed all of the findings that were used in order to collect data and enter it into the table, which was then cross checked by both authors separately. A concise report of four four articles included in the study is reflected in Table 1. The areas of interest included: population variables (number, age, and country), FFQ structures (type of FFQ, consumption interval, administration technique, portion estimation, and number of FFQ administered), reference technique utilized, type of denture used, and usage of FFQ validation methods by authors.

Table 1 Characteristics of included studies evaluating the use of food frequency questionnaire and its quality

Results

Risk of bias

The NOS assessment reveals that the studies by Jauhiainen et al., Savoca et al., and Muller et al. achieved the highest quality level with a score of 9, indicating robust methodologies and reliable findings. The study by Budiman et al. also demonstrated high quality, with a score of 8, although it had slight limitations in controlling confounding factors [Table 2].

Table 2 Newcastle-Ottawa scale (NOS) assessment of included studies

Discussion

In this systematic review, using standardized Dennis et al.[15] quality assessment method, we evaluated four studies which were focused on the denture wearer and used FFQ to assess the nutritional intake among them. FFQs are commonly used to measure nutritional status because of their simplicity, pragmatism, low cost, and low participant engagement, as well as their ability to assess dietary status over time.[23,24] However, in literature, there was a limited use of this instrument among denture wearer.[3]

Most of the studies in this review used interview method for administration of FFQ and found to be promising for assessing nutritional status of denture wearer. In contrast to self-administered FFQs, Cade et al.[4] found that when the FFQ was administered by an interviewer, the correlation coefficients have been increased.[3] The study done by Jauhiainen et al.[16] was based on self-administration which has been shown to be a valid method but mainly for assessing the habitual and long term food consumption.[16,24] Furthermore, it must be understood that as people grow older, they are more likely to develop memory problems. In this situation, retrospective approaches is ineffective and may be improved if a caregiver is available.[22] Since FFQs are known to overvalue energy consumption, using portion size in addition to the traditional reference approach tends to have some advantages.[3] In this review, most of the studies did not mention the estimation of portion size while Jauhiainen et al.[16] used standard cups for estimating the portion size. There was variation in number of FFQ items used for recording nutritional intake which might affect the overall outcome of studies. In a systematic review by Henríquez-Sánchez et al.,[26] an improvement in correlation coefficients (r 0·52) was seen when the number of food items included in the FFQ was >100 (r 0·47). The average number of food items used in the present studies included in this review was 99.[3] There was considerable variability between studies on methods of data collection, including consumption interval, reference method, and FFQ design. Because of this variance, it was impossible to compare FFQs directly in this study and similar was recorded by McLean RM et al.[27] FFQs are popular because they can approximate typical intake (over a set period of time) in a single interaction. While day-to-day variability is taken into account by FFQs that measure consumption over a month, but seasonal variance is not taken into consideration. A questionnaire that asks participants regarding their consumption over a period of 12 months will account for seasonal variance but may be more susceptible to recall bias, leading to higher sampling error.[28]

Overall, it has been reported that FFQ was valid and reliable tool for estimation of nutritional intake among denture wearer. Complete dentures or removable dentures, on the other hand, were found to eat less vegetables and fruit than dentate individuals. It was reported that edentulous full denture wearers ate a less healthy diet, consumed more surgary drinks, had lower Vitamin C and E consumption, and consumed less dietary fiber.[29,30] Almost half of all denture wearers admitted removing their dentures while eating at least some time, regardless of denture form. Hummel SK and colleagues[31] reported that the denture quality, chewing capability, and perceived chewing ability were not linked to diet quality among those with full dentures.[31] Others have shown that poor denture fit has been associated with lower dietary quality.[29,32]

Despite the fact that a patient’s traditional denture has a reduced masticatory capacity, they may adapt to the new ways of chewing and preparing food in order to maintain a healthy diet.[18] The mean FFQ score found improved with the duration of denture wearing; however, no significant changes were observed after 2 months. This may be due to adaption to the denture.[6] Moreover, Muller et al.[18] observed that conventional denture wearers did not avoid harder foods, even after chewing problems.

Conclusion

This systematic literature review presented a summary of the quality of studies performed on denture wearer using FFQs. The included studies and quality assessment have provided information on aspects of FFQ design that increase validity, such as the number of items included, consumption interval, portion size estimations, reference method, and administration method. Most of the studies used interview administration of FFQ, which found to be more acceptable in quality analysis. Since there was an insufficient data to compare various FFQ parameters among denture wearers, the data were narratively synthesized and presented. All the included studies in this review used previously validated questionnaires, instead of that validation study among denture wearer might give better picture of validity and reliability of questionnaire estimating nutritional intake.

Financial Support and Sponsorship

Authors received no financial support for this research project.

Conflicts of Interest

The authors declare that there is no conflict of interest.