Friday, 18 March 2016

East London says MS is more about Environment than Genetics

Christo Albor, Timothy du Sautoy, Narmadha Kali Vanan,
Benjamin P Turner,  Kambiz Boomla, and Klaus Schmierer
Ethnicity and prevalence of multiple sclerosis in east London

Mult Scler 1352458516638746, doi:10.1177/1352458516638746

Background: Incidence and prevalence rates of multiple sclerosis (MS) are generally higher in White populations than in other ethnic groups. Relevant studies in the United Kingdom were conducted over 30 years ago.
Objectives: To provide updated ethnicity-specific MS prevalence rates in the United Kingdom.
Methods: Electronic records from general practices (GPs) in four east London boroughs were queried for the number of people diagnosed with MS, grouped by ethnicity, into 5-year age bands. Compared against total registered GP patients in the area (c. 900,000), the age-standardised MS prevalence was calculated by ethnic group.
Results: The overall age-standardised prevalence of MS was 111 per 100,000 (152 for women and 70 for men), and 180, 74 and 29 for the White, Black and South Asian populations, respectively. The sex ratios (female:male) were 2.2:1, 2.1:1 and 2.8:1, respectively.
Conclusion: MS prevalence was considerably lower among Black and South Asian populations, compared to the White population, by 59% and 84%, respectively. However, compared to available data in Africa and South Asia, MS is several times more prevalent among Black people and South Asians living in the United Kingdom than their territorial ancestry.



Ethnicity-specific prevalence of MS in east London: crude (white bars) and age standardised (filled bars). 

Our medical students have been busy getting all People with MS attending Barts Health onto the BartsMS Database, however for this study we also teamed up with Kambiz Boomla and his colleagues at the Centre for Primary Care and Public Health of the Blizard Institute. 

Even the highest prevalence reported for any sub-Saharan African country, 0.24/100,000 in Ghana, is a small fraction of the prevalence of MS in Black people in east London (74/100,000). MS prevalence for people living in India (7/100,000) or Pakistan (5/100,000) was also much lower than for South Asians living in east London (29/100,000). 

While prevalence differences could be explained by fewer MS diagnoses occurring in less resourced countries, it is unlikely to explain the gulf in prevalence between these territories.  As summarised by The Times "Within one generation of being here the likelihood of them getting MS has multiplied... This strongly suggests an environmental factor.”

Or several thereof.  The next question is how to test - robustly and within an achievable time frame - whether altering factors for which there is strong evidence, such as EBV infection and low vitamin D, impacts on the risk of getting MS.

12 comments:

  1. Are there global maps of differing EBV prevalence in existence?

    When will the next news re. Charcot come out?

    ReplyDelete
    Replies
    1. Here's an accessible resource on EBV prevalence: http://www.ncbi.nlm.nih.gov/books/NBK47424/

      Have to defer to GG (Gold & Giovannoni) re second question!

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    2. Many thanks, Dr Schmierer.

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  2. Interesting, thanks for posting

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  3. Can some doc explain the relationship between VitD and/or UV and (EBV)viruses?

    Does sunlight help increase or decrease viral load?

    ReplyDelete
    Replies
    1. Here's the link to some previous work from BartsMS: http://www.tandfonline.com/doi/pdf/10.1586/ern.11.97

      The interaction between D an EBV may be key when it comes to designing a "doable" study of MS in east London (or elsewhere).

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  4. What about dual heritage?

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    Replies
    1. We don't have the granularity in this dataset.

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  5. why didn't you look at when people migrated and whether they are first second or third generation. geoffrey dean did this years ago!

    ReplyDelete
    Replies
    1. We are standing on the shoulders of giants including those of Geoffrey Dean and his studies in South Africa. Unfortunately, the east London GP dataset does not include year of migration; we're currently collecting this via the BartsMS Database, and hope we'll be able to map this onto the GP dataset, which is a little tricky due to governance issues, however important as we receive quite a number of out-of-borough referrals that are on our local (BartsMS) dataset. In turn, some pwMS in our catchment attend services out-of-borough. Prevalence estimates become inaccurate if you cannot exactly define the population you’re looking at. One should also remember that describing a population should not stop at generating hypotheses, but rather move forward and test them. In this sense our paper is the canvass for further research.

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  6. If a virus is implicated in MS, You can explain why the treatment is immunosuppressant ?

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    Replies
    1. Immunosuppression can mean killing B lymphocytes that are infected by EBV. Suppressing B cells is quite effective in MS.

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