We appreciate your concern regarding the KS-10 item domains. The reason we chose to use the general item value is that it is less burdensome than the longer versions and it is best practice to use the general score and not to directly try to analyse for each dimension. We are not sure that it is a fact that diet can not influence parent relations or social relations, if diet can help to improve quality of life then this may improve how an adolescent feels and their emotions which ultimately may have an influence on relations to others. However, we realise that we may miss out other findings and have mentioned this as a limitation, lines 496-497 and we appreciate your views on this matter. We have also incorporated more information about KS-10 reliability in measuring HRQoL, 236-244This is also a cross sectional study and so only associations can be established not causations.
Because the KQ-10 is a composite tests there is the likelihood to be some interaction with the sub-domains. Focusing only on the global KQ-10 scores is hiding the subdomain differences to diet. Diet is not expected to have any influence of parent relations, social relations or peers but your study may find an influence on psychological well-being and even school environment. This is the core of your study: does diet have an influence on psychological wellbeing? Remember the KQ-10 is made up of five subdomains (psychological well-being, autonomy and parent relation, social support and peers, and school environment) The fact is diet is no expected to change 3 of these KQ-3 subdomains and only one or two KQ-10 dimensions. Use all five of the KO-10 dimensions as your outcome measure not the Mean average global KQ-10 score. You may have a more important study if you do that, with a different finding to what you have just using the composite total.