#PHTwitJC 23: Smoking and Meningococcal Disease

Secondhand-Smoke-

Public Health Twitter Journal Club will meet for live Twitter discussion on Sunday 24th March, starting at 8.00 PM GMT / UK time).  All are welcome to contribute and pose questions using the hashtag #PHTwitJC. If you have never joined a Twitter chat before, there are some tips in the ‘About’ page linked above.

We will be discussing this research paper:

Murray et al (2012) Second hand smoke exposure and the risk of invasive meningococcal disease in children: systematic review and meta-analysis, BMC Public Health, 12:1062. Full text link

You may find it useful to structure your critical appraisal with this handy checklist (provided by the Dept of GP, Univeristy of Glasgow).

What is meningococcal disease?

picture of meningococcus bacterium

Meningococcal disease is a serious illness caused by a bacterium known as meningococcus.  In rare circumstances the meningococci can overcome the body’s defences and cause illness.  When this does occur, the bacteria can cause meningitis (infection and inflammation of the lining of the brain) and a severe condition that can spread throughout the body in the blood called septicaemia (blood poisoning).

For further information: HPA Meningococcal infection factsheet

Why is meningococcal disease a public health issue?

It is largely preventable cause of mortality and morbidity.  In the UK, the MenC vaccine has been part of the childhood immunisation schedule since 1999.  Meningococcal polysaccharide vaccines are available which cover serotype groups A, C, Y, W and W135 (source: WHO).

There is no available vaccine against serogroup B meningococcal disease (currently responsible for the majority of meningococcal infections).  Therefore it is of the utmost importance that health professionals and the general public remain alert to the signs and symptoms of meningococcal disease.  The Meningitis Trust provide good advice for what to look out for here.

Around 10% of meningococcal meningitis cases result in mortality, and this increases up to 50% for cases with meningococcal septicaemia.  However, if the disease is diagnosed early and treated promptly most people make a full recovery.  Cases who do recover occassionally suffer long-term effects, such as headaches, stiffness in the joints, epileptic fits, deafness and learning difficulties.

Paper summary

This paper aimed to provide an estimate of the size of the risk of second hand smoking (by different family members, and of pre-and post-natal maternal smoking) on invasive meningicoccal disease at different stages of childhood.  They performed a systematic review of 4 databases, and performed a meta-analysis.

They reported the following findings:

  • Second-hand smoking in the home doubles the risk of invasive meningococcal disease (with some evidence of a dose-response gradient)
  • Pre-natal maternal smoking tripled the risk of invasive meningococcal disease, and post-natal maternal smoking doubled the risk.

Discussion points

  1. Were the aims of this study clear? (consider the population, outcome measures, intervention)
  2. Was the systematic review comprehensive? (consider research designs included, inclusion and exclusion criteria, would all relevant studies have been identified?)
  3. Was the meta-analysis appropraite? (consider the similarity of study measures and outcomes, variations in quality or size)
  4. Do you believe the results? Could anything else explain these findings? (Consider whether the results are due to chance, bias, confounding or the truth?)
  5. What implications do the findings have for public health practice & policy?

We look forward to the Twitter discussion which will take place on Sunday 24th March at 8pm!  As always, do get in touch if you have any questions or comments

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