Is CLL more common among Ashkenazi Jewish people?
One of our members has asked me to back up my assertion in a previous article that a surprisingly high percentage of Ashkenazi Jewish people are vulnerable to CLL. She is my kind of a member, good for her! I hope none of you take things for granted just because someone on the internet said it was so. Challenge your sources to put their money where their mouth is, every chance you get.
I dug around a bit and here is what I came up with by way of a credible journal article linking CLL and Ashkenazi Jewish ethnicity. The paper is from Israel, where some of the cutting edge research is being done. The abstract and my discussion are below; you can read the full text of the article by clicking on the link provided.
Leukemia. 1998 Oct;12(10):1612-7.
Shvidel L, Shtarlid M, Klepfish A, Sigler E, Berrebi A.
Hematology Institute, Kaplan Medical Center, Hebrew University, Faculty of Medicine, Rehovot, Israel.
Chronic lymphocytic leukemia (CLL) represents 30% of all leukemias in Caucasians. In East Europe and USA the disease incidence is high while in Asia and Africa CLL is rare. The present study deals with 302 cases of B cell CLL and related disorders; 207 patients originating from Europe and America (Ashkenazi Jews) and 95 descendants from Asia, The Mediterranean or Africa (Sephardic Jews). The patients were recruited during 1975-1996 in a single center covering the Hashfela region — a Southern area of Israel with a current population of 430000 inhabitants. Incidence of the disease, clinical pattern, biological parameters, prognosis and outcome were investigated and compared in both ethnic groups. The results of this study show a high incidence of CLL in Israel. The mean annual age-adjusted incidence 4.3 per 100000 person-year is among the highest reported values. Our study confirms previous data on the prevalence of CLL in Ashkenazi compared to Sephardic Jews. The rise in CLL rate in the reviewed period occurred in both populations, mainly in the Sephardic group. The relative risk for Ashkenazies compared to Sephardics decreased from 6.0 in the 1975-1979 period to 2.4 in 1990-1996. A high rate of CLL was found in new immigrants from the former USSR with 26 cases de novo diagnosed and 11 prevalent cases not included in this series among approximately 60000 new immigrants in the area over the last 8 years. No differences were found in clinical, laboratory and immunological parameters at the time of diagnosis in the two ethnic groups. The follow-up showed a similar pattern in the disease evolution. A preliminary study of immunoglobulin heavy chain rearrangement performed in 14 patients showed no significant differences in JH hybridization in the early stages of the disease, but more aberrations in advanced CLL in the Ashkenazi group. Our findings suggest that ethnic origin of the patients itself does not affect the biological and clinical behavior of this disease.
This study talks about 302 cases of CLL diagnosed at the same institution in Israel over a period of 20 years (1975-1996). Of these 302 patients, a whopping 69% were Ashkenazi Jews, while 32% were Sephardic Jews. This is the clearest data I have seen demonstrating the preponderance of Ashkenazi Jewish people stricken with this disease.
More troubling is the trend towards higher incidence of CLL in the region over the years. The present population of the southern area of Israel served by this institution is around 430,000. The authors point out that due to immigration the population in this part of Israel has expanded and therefore we may conclude there were fewer people living there back in 1975-1990. The population base is higher now.
As you can see from the graph above, the total incidence (number of cases diagnosed per 100,000 people per year) has increased quite a bit over the time period, from 2.5 to 4.3. That is a 72% increase in incidence of the disease over a 20 year period. The trend continues to reflect emphasis on Ashkenazi ethnicity. In the Ashkenazi group the incidence is astonishingly high at around 7 cases per 100,000 people per year. Looking at these trend lines and larger population base of today, it is reasonable to expect many more people are diagnosed with CLL today in Israel.
The authors did not see any significant difference between the two groups as far as disease severity or clinical progression is concerned. They explore the impact of diet, occupational exposure to pesticides and farm chemicals, increased life spans due to better medical care, etc. among the factors contributing to the increased incidence of CLL in this community. Please read the full article to get all the details.
CLL Incidence in the USA
As a comparison to the situation reported in Israel, here are the statistics of CLL incidence in the USA, reported by the NCI in their SEER surveys. Below is a table of the incidence rates of CLL by race, between the years 2002-2006.
The average incidence across the whole country, men and women, is 4.1 cases per year per 100,000 people. It is estimated that 15,490 people (9,200 men and 6290 women) will be diagnosed with CLL in the USA in 2009, and this year there will be 4,390 deaths due to CLL in the country. Men are more likely to get CLL than women, and incidence increases with age. I have read Minnesota leads the nation in CLL – attributed to the heavy use of farming chemicals in that agro state. The other “hot spot” is Brooklyn and New York in general, with its high percentage of Jewish people. (I will publish the link and abstract when I find it again. My filing system is getting overwhelmed with the number of articles I have collected over the years).
SEER has this to say about life time risk of getting CLL in the USA:
“Based on rates from 2004-2006, 0.47% of men and women born today will be diagnosed with chronic lymphocytic leukemia at some time during their lifetime. This number can also be expressed as 1 in 212 people will be diagnosed with chronic lymphocytic leukemia during their lifetime”.
Based on recent research with familial CLL clusters, we know this risk goes up approximately 8.5 fold in people who have first degree relatives with CLL. For this select group (with first degree blood relative with CLL) the risk is therefore in the region of 1 in 25. It came as a bit of a shock to me.
While the NCI does not specifically mentions Ashkenazi ancestry as a risk factor, it does list among the risk factors “having relatives who are Russian Jews or Eastern European Jews”. Same thing, no difference (I think).
We don’t yet know what exactly causes CLL. But we do not a few things. Here they are:
- Men are more likely to get CLL than women.
- Risk of getting CLL goes up very significantly with age.
- Some ethnic groups are more prone to CLL than others. In particular, Ashkenazi Jewish people are more prone to CLL than other ethnic groups.
- CLL is a familial cancer. People with first degree blood relatives who have CLL are more likely to get the disease than the general population (8.5 times more likely).
- In some families with multi-generational clusters of CLL, kids and grandkids with CLL are likely to get the disease at younger ages, and it may be more aggressive as well. This is called “anticipation”.
What does this mean in the real world? As I wrote in an earlier article, the worst day in your life is not when you were diagnosed with CLL. That “honor” is reserved for the day you are told a beloved child or grandchild has inherited this incurable cancer from you.
How then do we protect our kids? What do we do? I have struggled with this issue myself. In spite of our combined best efforts, my beloved husband died, a victim of aggressive CLL. We have a much beloved daughter. How do I protect her? What can I do? Here are some thoughts that I would like to share with you.
- Knowledge is our best defense. Stay involved, stay informed. How can you fight something you do not understand?
- Support new research and clinical trials. That is the only way we are going to get improved therapy options for our kids down the road.
- Support patient advocacy groups. Compared to more “popular” cancers such as breast cancer or prostate cancer, or more deadly cancers such as non-small cell lung cancer, CLL is a Cinderella that has not yet met her fairy godmother. Our numbers are small, it is still thought of as the “good cancer”. Our voices will not be heard unless and until we mobilize, learn to bury our petty differences and jealousies and work together.
- Educate our kids in the things that they can do to stay healthy. That means eating a healthy diet, maintaining good body weight, exercising regularly, getting regular medical checkups and vaccinations as they are needed, stay the heck away from smoking, drugs etc. You and they know the list. It is a question of getting it into practice. I am told Jewish mothers and Indian mothers excel in the art of ‘guilt-tripping’. Frankly I think all mothers learn this skill early on. How about using it to help your kids stay healthy? A little bit of loving nagging goes a long way…
- Please teach your kids not to ignore chronic inflammatory conditions, not to treat low level infections such as “walking pneumonia”, chronic sinusitis like they are a joke, to be ignored. If they can be dealt with, if the inflammation can be brought under control, so much the better. Multiple episodes of pulmonary infection / inflammation have been cited as a common theme in people who go on to be diagnosed with CLL.
- I understand supplements such as fish oil (omega-3 fats) and adequate level of vitamin D3 can help keep inflammation at bay. But please be sure to do your own due diligence and check with experts before you start any supplements! Self-medication can sometimes be counter productive (mega doses of vitamins A & E are not good for cancer patients, for example)
- Ethnic minorities are not well represented in stem cell banks; they are harder to match when the need arises for allogeneic stem cell transplants using matched unrelated donors (MUD). While cord blood promises to be a good source of stem cells and makes it possible to find matches for many more patients needing transplants, even here donor recruitment lags behind need in ethnic minorities. Get the word out folks. Get your communities understand the need for more donors (both adult stem cell donors and umbilical cord blood donors). Without grassroots efforts to expland our donor base we will continue to have patients dying because they cannot find a suitable donor for a life saving stem cell transplant.
I am sure you have your own thoughts on the subject. Let’s hear them. I am delighted more and more of you are taking active part in the discussion that follows each article on Updates. Even more amazing, everyone has been on their best behavior. I have not had to take anyone to task for lack of politeness or straying from our comment guidelines (on topic, no politics, no religion, no snake oil, no heavy-handed ‘marketing’, no practicing medicine without a license). No “trolls” here, no tin foil crowd! If this site continues to be a class act it is because of you guys. I am so proud of you.