The study aimed to investigate if anxiety in adolescents is associated with the occurrence of asthma in childhood or, in contrast, if anxiety in children precedes asthma, analysing parental reports from 9369 children at two age points (4–5 and 14–15 years old) and from two cohorts of the Longitudinal Study of Australian Children (LSAC).
The topic is timely and offers original issues. Evidence has suggested a bidirectional association on both the effects and onset of asthma and anxiety. However, the temporal order between asthma and anxiety is unclear, and the scale of the literature on prospective associations of these conditions is limited for children and/or adolescents. Many of the previous studies had a cross sectional design and were therefore unable to determine the direction of the association between asthma and anxiety.
The main strengths of the present research are the large sample size and the longitudinal design.
The major concern is related to the tool used to measure anxiety.
The Strengths and Difficulties Questionnaire (SDQ) is a brief behavioural screening questionnaire about 2-17 year olds (4-17 in parents form).
The 25 items are divided between 5 scales:
1) emotional symptoms (5 items)
2) conduct problems (5 items)
3) hyperactivity/inattention (5 items)
4) peer relationship problems (5 items)
5) prosocial behavior (5 items)
In low-risk or general population samples, it may be better to use an alternative three-subscale division of the SDQ into 'internalising problems' (emotional+peer symptoms, 10 items), 'externalising problems ' (conduct+hyperactivity symptoms, 10 items) and the prosocial scale (5 items) (Goodman et al, 2010).
So, the SDQ doesn't measure anxiety, it rather measures "emotional symptoms" or "internalizing problems" (emotional problems+peer symptoms). Authors reported that “the three items related to anxiety in the emotional scale of this questionnaire were considered to assess anxiety: 1.“Many worries or often seems worried, 2. “Nervous in new situations. Easily lose confidence” 3. “Many fears. Easily scared”. It is not clear on what basis these 3 items of the "emotional symptoms" subscale are considered valid for specifically measuring anxiety. It would be helpful if the authors explained the reason for choosing an “improper” use of the SDQ to measure anxiety instead of using one of the many validated tools that measure the presence of anxiety symptoms or disorders in children and adolescents. The studies cited in the article used specific validated questionnaires for the assessment of anxiety (e.g. SCARED, STAIC) or, alternatively, they used validated behavioural screening tools (e.g. CBCL, Rutter Questionnaires) similar to the SDQ, for measuring internalizing/externalizing behaviour, and not specifically anxiety.
Rather than anxiety, it would be more informative and appropriate to focus the present article on "emotional symptoms", using all the 5 items of the subscale of the SDQ, or on "internalizing problems", using the emotional+peer symptoms subscales as required by the original manual of the SDQ. It would also be interesting to have the results relating to the other subscales of the SDQ and/or to externalizing symptoms.

All previous comments have been adequately addressed. The manuscript has been improved in light of the amendments. There are no further comments.