Question 1
What do you feel are the strengths and weaknesses of the FFQs used in this study? Are there any changes you would make to the format of the FFQs?
posted by lynn2552 @ 11:50 AM
8 comments
ISU Dietetic Internship Journal Club
Objective: To become familiar with current scientific literature on a variety of nutrition topics and to gain experience in gathering, organizing, critically evaluating, presenting and facilitating group discussion of the literature and the implications to practice.
8 Comments:
Strengths of the DHQ is its length, in that it attempts to address all areas of calcium intake (although that can be seen as a weakness as well), attempts to address portion sizes to accurately estimate intake (again can be seen as a weakness).
Weaknesses of the DHQ include its length, underestimation of the calcium due to portion size options, data base that analyzed the DHQ underestimated calcium, and the questionnaire did not differentiate between regular and calcium fortified foods (like OJ).
Strengths of the calcium questionnaire include its detailed information/directions to help the subjects determine their portion size, open-ended sections to write down what is not covered in the questionnaire (although that can make analysis difficult), subjects write how often they consume the foods, and it was recently updated.
Weaknesses include the fact that the subjects have to write a lot, they may not be able to recall what they ate without help, and the open ended sections may contribute to overestimation.
Strengths of the short calcium questionnaire include the fact that it is short.
Weaknesses include the fact that portion size selection is not an option; rather they estimate how many of a certain portion they ate, it is seen more as a screening tool not an accurate estimate of calcium intake.
If you could combine all the strengths of the FFQ’s and try to eliminate the weaknesses you could potentially have a very accurate FFQ.
DHQ: A major strength of this tool is its very large database; it allows people to look up a large number of different foods that they may consume in a selected time period. A weakness for this study was that the DHQ isn’t specifically aimed at judging Ca intake, so it seemed to be a relatively weak measure for this. Another problem could be the length of the survey, requiring the pt. 60 minutes to fill it out could be a problem in a lot of circumstances.
Ca Questionnaire: The strengths of this tool were that it was specifically designed to measure Ca intake levels, and the portion sizes seemed to be appropriate for most individuals. The only weakness could potentially be its time requirement, 15-30 minutes might be a problem, but for the accuracy of its measures, it could very well be worth that amount of time rather than using a “quicker” instrument.
Short Ca Questionnaire: The major strength of this tool was that it is quick (requiring only about 10 minutes) and specifically measures Ca intake levels. A potential weakness is that the database only contains 25 items, which could leave a lot of items up for debate when the pt is filling the survey out.
While the length of the DHQ is great because it is thorough and more than likely would yield the most reliable conclusion, this could also be a draw back. Because this is a 36 page questionnaire, individuals may be less willing to complete the last pages as well as the first pages.
Like Karlie said the Calcium Questionnaire was design to identify strictly calcium in the foods specified which is a great aspect of this questionnaire. Although like the DHQ, it may be a bit lengthy to have the most thoughtful answers provided.
A major shortcoming of the Short Calcium Questionnaire could be the fact that foods are grouped together which could alter the accuracy of the calcium total. These foods are grouped by calcium content per serving but the content is still somewhat variable per food product. THe fact that this survey is not as long as the other 2 may make it easier for patients/individuals to devote the amount of time required for it.
First and foremost, FFQ are the most widely used tool used to measure diet analysis. So in order for them to be 100% accurate, the person filling a FFQ out must be completely accurate. Right off the bat, this would be a sign that you need to really analyze what people are writing to make sure they are not leaving little details out!
I believe that a strength of the DHQ was that it was very detailed, but in the same sense I will contradict myself by saying that the length could have been a problem as well. When filling out a FFQ, many people will not even be able to list off everything they ate the day prior, let alone for the past 12 months. I feel as even though this FFQ measurement will be accurate if taken seriously, it is extremely too long (for both the client/pt and RD/medical professional).
Since this study is tailored directly to Ca intake, I believe that the questionnaires directly related to Ca will have more accurate outcome. As for the Calcium Questionnaire, I believe a strength is that it was developed by professionals in the fields that are concerned with this type of finding. They probably know better than anyone which type of questions to ask to get straight to the point! A downfall to the Calcium Questionnaire would be that again, it is somewhat long!
For the Short Calcium Questionnaire, a strength would be that it is to the point, no length process involved. Another strength would be that it is for the most part extremely accurate even being so short. My concern with the Short Calcium Questionnaire is that it was recently developed by an author of the study. My question related to this concern is how much knowledge does he/she have regarding this topic…is it truly enough to make up an accurate survey for Ca intake?
DHQ: Due to this form of FFQ being so lengthy, patients will be able to look up several foods making the DHQ a more comprehensive FFQ. A downfall to the DHQ is the length. Many patients do not want to fill out a 36 page survey. Many patients may begin the survey with good intentions but neglect to fill the remainder out due to the time factor. Also, the DHQ is not directly assessing calcium intake.
Calcium Questionnaire: The length of this study is an improvement when compared to the DHQ, however it is still a bit lengthy. This assessment is used specifically for calcium intake, which makes it a better form of assessment when compared to the DHQ.
Short-Calcium Questionnaire: Although the length of this instrument is an improvement when comparing to the other assessment instruments, it may be too short. This instrument only reflects major dietary sources of calcium and may not allow for a complete analysis of one’s diet.
As many others have said the length of the DHQ and longer Ca questionnaire can be both a strenth and a weakness.
It is a strength to get more information but there are only benefits to a point and then the increased length will no longer contribute to more accurate results but will actually level off.
The key is to find that point in which you have asked enough without going overboard.
Also, while FFQ are a common, simple, efficient way of getting diet information from clients they are also a weaker way of obtaining information then to do a oral recall with the person.
When you actually talk with someone you can be sure that they fully understand portion sizes or the patient can always question the RD if they are confused about something.
The shorter calcium questionnaire is beneficial in that it does not overwhelm the patient however it may not be elaborate enough to get the most accurate results.
As with any good questionnaire it should be continually tested and updated for reliability and validity.
-DHQ
Strengths: Very detailed and dates back to frequency of intake in past year
Weaknesses: Too long which may affect accuracy (may lose patient's attention), outdated (portion sizes, absence of calcium-fortified foods)
-Calcium Questionnaire
Strengths: Updated in 2002, thus includes new foritified products and open-ended sections to include any fortified/supplemental foods or beverages consumed. Also includes detailed reference sections for portion sizes.
Weaknesses: Respondents had a tendency to overestimate calcium intake (due to inclusion of fortified products on questionnaire)
-Short Calcium Questionnaire
Strengths: Concise and good when doing a quick screening, includes section on supplements/antacids
Weaknesses: Because it is so short, it requires that the respondant write in their # of servings eaten in a week (may not be the best for accuracy)
DHQ
Benefits: use while taking into account many nutrients are being assessed, pick out from food list and from a range of portion sizes, ask about supplementation, analysis from “optimal scanning”
Downfall: the length of questionnaire will increase likelihood pt may not complete to satisfaction of clinician, there is not a distinction b/n some of the Ca fortified and non fortified products.
Ca quest
Benefits: use while assessing the usual intake, individualized treatment plan, open ended-pt can write in answer, portion size reference to help fill out questionnaire, asked about supplementation, 2002 updated list (show fortified ca products available), standard spreadsheet software-accurate and consistent analysis,
Downfall: it might be outdated because it is based off of a 1987 questionnaire, times change, America has different eating pattern, hard to remember what has been eaten a month ago, accuracy is questionable, may not know names of products using, people may not know if they are eating ca-fortified foods (even with the list)
Short ca Quest
Benefits: easy and quick tool to use for estimating ca intake for screening a pt., length is short-not over burdening the pt or clinician,
Downfalls: may not have the entire picture if it is short in length, no portion size to gauge the amount consumed, Could not use to compare with overall dietary intake-just use as a quick screening tool
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