"Across the full range of scores at a population level, each 1-point increase in inattention at age 7 years is associated with worse academic outcomes at age 16."
That was one of the conclusions reached in the study by Kapil Sayal and colleagues  (open-access) drawing on data derived from the Avon Longitudinal Study of Parents and Children or ALSPAC to those in the know. This initiative has also recently produced some other intriguing results on the potential long-term effects of bullying for example (see here).
"Matching of the ALSPAC database with the administrative National Pupil Database (NPD, the central repository in England for pupil-level educational data) provided details of the children's results in the General Certificate of Secondary Education (GCSE) examinations at age 16 years." For those resident in England, Wales and Northern Ireland, GCSEs are probably a familiar concept (they were the starting point for my own academic achievement record). For everyone else, GCSEs are normally sat at the end of the school journey (16 years) and form the start of the typical educational achievement hierarchy leading into A-levels, university degree and beyond. "In total, GCSE attainment data were available for 11,640 children (83% of the core ALSPAC sample)."
The Development and Well-Being Assessment (DAWBA) was completed by parents and teachers of participating children when aged 7 years old. Similar to other discussions on this blog mentioning the DAWBA (see here) it relates "closely to DSM-IV items and focus on current problems and associated impairment." For the purposes of the Sayal study "the key variables of interest relate to inattention, hyperactivity/impulsivity, and oppositional/defiant behaviors." Various other potential confounders such as child cognitive abilities and parental social class were also measured and taken into account when it came to the final analyses.
Following some number-crunching the authors concluded that their results potentially "highlights the adverse effects of early childhood behavioral difficulties on educational outcomes in adolescence" specifically based on inattention symptoms: "inattention, particularly if noticeable to a parent or teacher, is a stronger predictor than hyperactivity/impulsivity of later academic difficulties." Disruptive behaviour disorder (DBD) and oppositional/defiant symptoms were also independently linked to worse academic outcomes in boys.
I know that such findings are probably not totally unexpected in terms of issues such as inattention potentially impacting on learning ability/capacity/enthusiasm subsequently also being reflected in exam results, but the results do put a peer-reviewed, evidence-based perspective on things. Authors also note that: "teachers and parents should be aware of the academic impact of early behavioral difficulties, and, in particular, the risk associated with subthreshold difficulties." I might add that such results do not rule out other factors as playing a role in academic outcome as per other recent data .
Insofar as what can be potentially done to mitigate such symptoms and their potential impact on academic performance, the authors offer a few suggestions including: "strategies that might help to optimize examination performance during teenage years include time management and organization skills (throughout the course of study), prioritization of key work, minimizing distractions, examination revision, and within-examination strategy." All well and good (and discussed by other authors ) I say but perhaps one might also look to 'tackling' issues such as inattention in other ways too. Take for example the recent paper from Bos and colleagues  (see this post) discussing their results based on supplementation with omega-3 fatty acids specifically on inattention symptoms. Probably not suitable or useful for every child with attentional issues, but certainly worth quite a bit more investigation looking for potential best responders based on the idea that good nutrition might be an important part of good mental health. Oh, and how about looking at sleep and even chess? 
Music: Cannonball - The Breeders.
 Sayal K. et al. Childhood behavior problems and academic outcomes in adolescence: longitudinal population-based study. J Am Acad Child Adolesc Psychiatry. 2015 May;54(5):360-368.e2.
 Peyrot WJ. et al. The association between lower educational attainment and depression owing to shared genetic effects? Results in ~25 000 subjects. Molecular Psychiatry. 2015. April 28.
 Ciesielski HA. et al. Academic Skills Groups for Middle School Children With ADHD in the Outpatient Mental Health Setting: An Open Trial. J Atten Disord. 2015 Apr 29. pii: 1087054715584055.
 Bos DJ. et al. Reduced Symptoms of Inattention after Dietary Omega-3 Fatty Acid Supplementation in Boys with and without Attention Deficit/Hyperactivity Disorder. Neuropsychopharmacology. 2015 Mar 19.
 Blasco-Fontecilla H. et al. Efficacy of chess training for the treatment of ADHD: A prospective, open label study. Rev Psiquiatr Salud Ment. 2015 Apr 21. pii: S1888-9891(15)00048-8.
Sayal K, Washbrook E, & Propper C (2015). Childhood behavior problems and academic outcomes in adolescence: longitudinal population-based study. Journal of the American Academy of Child and Adolescent Psychiatry, 54 (5), 360-36800 PMID: 25901772