Reduced Screen Time is Associated with Healthy Dietary Behaviors but Not Body Weight Status among Polish Adolescents. Report from the Wise Nutrition—Healthy Generation Project

Reviewer

Authors

Language and spelling

Thank you very much for the language corrections made to the manuscript. We have introduced all the changes as recommended.

Abstract

line 27: SCT abbreviation problem

line 31: "half higher"

This is a good point indicating our mistake. We have changed this throughout the manuscript. It has been marked in red in the manuscript text.

Yes, it was our language irregularity. For clarity, we have changed the descriptive form ("half higher") to number and now it reads like:

"The chance for meeting the recommendation for ST in a group of girls (regardless of age) was almost 50% higher as compared to boys."

Introduction

line 46: lacking parenthesis

line 61: revise sentence

line 70: COSI

line 72: spelling "hour"

line 74: simplify

line 87: revise the sentence

It has been added.

The sentence has been revised. Now it reads:

Technological progress, digitization of all areas of life, as well as the increasing availability of electronic equipment, including computers, smart phones, televisions, play stations, software and computer/video games, affect children and adolescents behaviors, and cause a prolonged time spent passively, in front of the screen.."

It has been explained and now reads: " the Childhood Obesity Surveillance Initiative (COSI) study..."

It has been changed as suggested.

The sentence has been revised. Now it reads: "More and more concerns have been growing about the impact of screen time (especially the use of mobile phone), on children and adolescents health and well-being."

The sentence has been revised. Now it reads: "Such a rapid "digitization" of children and adolescents' surroundings causes dramatic changes in their lifestyle. This shift has been observed for a relatively short time - over the past decade."

Results / Tables and Figures

lines 200-201: why use different letters?

line 205: see comment in abstract

line 206: revise the sentence

line 212: SCT

line 218: revise the sentence

line 238: Dairy is not believed to be nutritional by all.  

The different letters have been used to stress the differences in p value: p < 0.05 in the first case, and p < 0.001 in the second case

Thank for this comment. It has been changed for: 50% higher. It reads: " The probability of meeting the recommended screen time was almost 50% higher among girls compared to boys"

The sentence has been revised. It reads in the new version:   "With the youngest age group as a reference, the odds of not exceeding the screen time recommendations decreased from about 80% among 14-year-olds to less than 60% in the oldest group."

It has been changed to SC throughout of the manuscript.

The sentence has been revise. Now it reads as: "A significant relationship between screen time duration and the majority of analyzed eating behaviors was observed. There was no relationship between SC and drinking milk or milk beverages every day among girls and consuming whole-grained bread every day among boys"

We partially agree with the comment. However, in Poland dairy products are traditionally an important element of the diet. Their consumption (in the amount of 2-3 servings per day) is recommended by national nutrition organizations. Milk and milk beverages (especially fermented) are placed in the Food Pyramids and their consumption is recommended for children, adolescents and adults.

Discussion

line 274: This body of research is large. I would focus on samples and measures that were similar to your study.

line 346: Unfortunately, self-report measures have a lot of bias and have found to not be the most reliable.

We partially agree with the comment. Discussion has been divided into more subsection to improve readability. However, following the comment we deleted some part of this section.

Thank you for this comment. Indeed, this sentence should only apply to parameters related to the assessment of body weight status and so it has been changed. It reads now: " An important strength of this study is a large and random sample size and the use of valid and reliable measures to assess the study variables (e.g. criteria for assessing the body weight status). " Possible bias related to self-reporting are listed in the limitations: " Secondly, the screen time duration and dietary behaviors were self-reported."

Reviewer

Authors

Language and style

The manuscript is well-written. I only stumbled across very few typos /stylistic inaccuracies. For instance:

- abstract (and later on): “half higher”

I do not understand what that means and what the authors are trying to say. Is it maybe double the size? Half the size? Half indicates a decrease whereas higher indicates an increase. Please rephrase.

Line 53: you use the words “computer” and “PC”. I recommend only using one word. Otherwise, it indicates that you mean different things but from my understanding, you refer to the same one thing in both cases.

Line 78: full stop missing.

Line 86: adolescents’

Line 138: full stop missing.

Line 141: Body size - do you mean body height or body weight?

Line 148: answerS

Line 181: Typo – Ddescriptive

Line 238: On the contrary: I do not really see how this is contrary.

Line 259: increased WITH age

Once you spell it Cramér and once it is spelled as Cramer.

Abstract:

For clarity, we have changed the descriptive form ("half higher") to number and now it reads like:

" The chance for meeting the recommendation for ST in a group of girls (regardless of age) was almost 50% higher as compared to boys."

This is a good point, terminology (computer) has been standardized throughout the text.

A dot has been put at the end of the sentence.

This has been corrected as suggested.

A dot has been added at the end of the sentence.

This applies to dissatisfaction with body weight - this has been clarified in the text.

This has been corrected as suggested.

This has been corrected as suggested.

A good point, we have changed and it reads as: "Whereas unfavorable eating behaviors such as skipping breakfast, low consumption of milk products, fruits, vegetables, fish and whole-grain bread were related to each other."

This has been corrected as suggested.

This is a good point, spelling (Cramer) has been standardized throughout the text.

Thank you very much for the language corrections.

Abstract

You introduce the abbreviation ST and later, you work with SCT, which seems to refer to the same thing.

This is a good point (also from the second reviewer) indicating our mistake. We have changed this throughout the manuscript. It has been marked in red in the manuscript text.

Introduction

Maybe I overread it but I am missing some rationale / some explanation why you chose to work with an adolescent sample. I can think of many reasons why this is important and interesting and I suggest you share this importance with the readership.

We agree with the comment that the reason for choosing this population should be more stressed. We added some explanation with literature quoted, and it now reads as:

"Research in this population group is particularly important because lifestyle behaviors (e.g. unhealthy diet and physical inactivity) are modifiable and usually established during youth or young adulthood [15]. The transition from childhood into adolescence is associated with a combination of stressors, which can have a significant impact on individuals' health lifestyle choices [16]. Furthermore, a good health status, especially in relation to normal body weight early in life, reduces the risk of obesity and diseases related to excessive body mass later in life [17]."

Material and methods

Maybe it is obvious to the readership but I would appreciate a short explanation for “stratified sampling method”.

This statistic method refers to the sampling designs where the examined population is partitioned into several subpopulations, called strata, and sample draws are made independently across each strata. Our strata are listed in the section "Study participants":

" The sampling was stratified by: 1) province (based on administrative division); 2) location (large, medium, small city and countryside); 3) the type of school (secondary and upper secondary)."

Stratified sampling improves the efficiency of the survey estimates over the sample random sampling. For these reasons, stratified sampling is very popular in practice.

Simply, in this method we draw a representative number of schools from each subgroup (from each province, location and type of school) from a large general group of 2058 enrolled institutions.

We hope that this explanation are sufficient, this statistic method is used in many studies [example: https://www.ece.iastate.edu/snt/files/2019/01/sss-edbt-2019.pdf].

Results

The results section begins with the demographic information. Please also add the numbers or percentages of girls and boys. This information is currently missing.

Line 205: “When adopted …” something is not adding up with this sentence, please rephrase.

These values were given earlier, i.e. in line 133 (section Study Participants). However, we agree that they should be presented in the results section. Now it reads:

"A total of 14,044 adolescents (53.8% girls and 46.2% boys) ..."

We agree with the comment and rephrased it. Now it reads:

"With the youngest age group as a reference, the odds of not exceeding the screen time recommendations decreased from about 80% among 14-year-olds to less than 60% in the oldest group."

Discussion

In my view, the discussion section would benefit from the addition of more subsections. There is only one subsection (study strengths and limitations). I recommend that the first part of the discussion should also be organised in subsections.

Line 273 ff.: “common opinion” sounds very speculative. Please add some reference or some explanation or rephrase.

The gender difference the authors report is in my view very interesting. It should be discussed a bit further in the discussion section or at least it would be worth mentioning that the reasons for this gender difference should be further investigated.

We agree with the comment and divided this section into subsections:

Screen Time Behaviors; Screen Time and Body Weight Status; Screen Time and Dietary Behaviors

This section has also been slightly shortened, as suggested by a second reviewer, which we believe improves readability.

We totally agree with the comment. We modified this section with literature quoted and now reads as:

"Therefore, our findings put into question previous observations [36,37] about the greater physical activity of boys compared to girls, and show the need for gender focused educational activities."

We agree that the observed gender differences are very interesting. However, in this manuscript we focus mainly on the relationship between ST and dietary behavior and body weight status (not just the screen time duration/adherence to ST recommendation, where the differences for both sexes were most visible). In the case of SC and dietary behavior, differences for sex were observed for only one determinant, i.e. vegetable consumption. Therefore, we prefer not to focus on discussing the relationship between gender and screen time, but we see the need for further research in this regard. We added this postulate and it is read now as:

"However, the observed effect of gender on the screen time duration requires further investigation."

We are currently preparing a manuscript on the adolescents' perception of body weight/size and influencing factors, and in this manuscript we have largely focused on gender differences.

Tables and Figures

Table 2: abbreviations (CI) need to be explained

Please report the number of girls and boys

Table 3: OR needs to be explained

Please report the number of girls and boys

Figure 1: n should be reported here

All these comments were introduced in the text (changes marked in green) to improve the readability of tables and figures.

OR, odds ratio; CI, confidence interval

Girls n = 7553

Boys n = 6491

total n = 14,044