Dear Dr Williams-Green,

You are to be congratulated on drawing attention to the importance of knowing your 'sickle status'. In fact, one could broaden this recommendation to knowing one's 'haemoglobin genotype' since this refers to the common genes (HbS, HbC, beta thalassaemia), which put one at risk of having a child affected by sickle-cell disease.

These genes occur in 15 per cent of Jamaicans, so over 400,000 Jamaicans are at risk of having an affected child. Whether you have an affected child depends on your choice of partner since if one parent is normal, you cannot have a child with the disease. So, with this information, sickle-cell disease could be prevented. This has already been achieved in Bahrain where premarital screening for the sickle-cell gene has halved the frequency of affected births.

Now the challenge must be to see whether informing people of their carrier status at younger ages will empower them to select partners who will avoid an affected child. In the parish of Manchester, a study has been under way for two years, offering detection of these haemoglobin genes to the senior schoolchildren of the 15 secondary schools in the parish. They are given permanent laminated cards with their genotype and counselling is given to the identified carriers. To see whether this information will decrease the affected births, newborn screening has been set up in the three maternity units in the parish.

This project is funded for the next five years by the National Health Fund and the Alcoa Foundation.

Hopefully, the Manchester project will provide the Jamaican and other governments with a model for prevention of this disease. More can be learnt about this project from the Sickle Cell Trust (Jamaica), 970-0077 or at sicklecelltrustjamaica.com.

Graham Serjeant

14 Milverton Crescent

Kingston 6.

Dear Dr Williams-Green,

A very good article. I wish that all men would read this article and take heed. During my pregnancy, I was tested forsickle-cell traits and given the all clear. When my daughter was a few months old, I was called in for an appointment and given the shocking news that she had sickle-cell traits. My spouse still refused to be tested.

- Concerned mother

Dear Reader,

Thanks for your commendation. Your experience underscores the importance of both prospective parents knowing their sickle-cell status. Fortunately, persons with the sickle (AS) trait are asymptomatic. However, with a 10 per cent prevalence of the sickle (AS) trait in our population, it is important for everyone to know his/her status to reduce the likelihood of parenting children with the serious SS disease.

- Pauline Williams-Green

The salt monster

Dear Ms Brown,

With regard to your article, there are many studies, of course. We feel the basic controversy is rooted in the different questions that are being asked. The researchers at St George, very anti-salt folks, focus attention on blood pressure impacts of salt reduction - which are real. We, as you may have read on our website, feel the proper research question should be: Are health outcomes improved if dietary sodium is reduced? On this point, the only controlled trial shows greater risks, and there is some variation among the several observational studies (20), but the greater number showing any change show additional risk of low-sodium diets while only a couple show any benefit whatsoever.

Dietiticans should not ignore the fact that low-salt diets induce increased insulin resistance, sharp increases in plasma renin activity and sympathetic nervous system activity, and a disturbing elevation of aldosterone production. That is why the evidence-based Cochrane Collaboration does not find evidence supporting general reduction of dietary sodium.

- Dick Hanneman

Send questions and comments to our health specialists at Your Health, c/o The Gleaner, 7 North Street, Kingston; email: yourhealth@gleanerjm.com. Unless otherwise indicated, letters and the specialists' responses are usually published.