Increases in testicular cancer may be linked to the rise in maternal b
http://www.100md.com
《英国医生杂志》
A new epidemiological study has found that incidence of testicular cancer followed changes in maternal weight before, during, and after the second world war and may therefore be linked to maternal body weight.
During the war, when energy intake and weight went down, so too did the incidence of testicular cancer, according to the results of the research in the International Journal of Cancer (2005;116:327-30).
"Our results further support the notion that testicular cancer is an example of a civilisation disease associated with a Westernised lifestyle with increase in obesity, obesity associated cancer forms, and diabetes type 2," say the authors, from the Cancer Registry of Norway, Oslo University College, and Rikshospitalet University Hospital.
Since the 1950s, the incidence of testicular cancer in the West has increased, and a number of theories have been suggested for this, from chemicals in the environment, to fetal exposure, to increased levels of oestrogen.
"It has been discussed for a long time whether exogenous endocrine disrupters may affect the pregnant mother and her offspring, but the use of the vast majority of manmade chemicals started to expand after . Since most of the men developing testicular cancer are 20 to 45 years old, it is reasonable to look for changes in natural risk factors taking place as early as 1920-30 to explain the increased incidence of testicular cancer since the 1950s onward," say the authors.
The aim of the study was to investigate whether maternal weight was associated with the incidence of testicular cancer using a unique Norwegian database that includes men born around the time of the second world war when the nutritional conditions changed due partly to a 15%-20% energy restriction imposed on the Norwegian population.
In the study, the authors compared data for a random sample of women giving birth in Oslo, Norway, in 1931-55 with the cancer incidence among men born in the whole country in the same period. The first 10 women a month to meet all criteria were included in the study, making 120 women a year and 3000 in total. Among all men born in Norway, all the 1790 patients with testicular cancer who were born 1931-55 and those diagnosed at the ages of 21 to 45 years were included.
The results show that the rates of testicular cancer among those born in the war years did drop. The rate in the period 1936 to 1940 was 10.3 per 100 000 person year, dropping to 8.7 in the 1941 to 1945 period, and then rising again to 11.6 in the five years after the war. In the same periods, the average maternal weight of women giving birth in Oslo dropped from 72.28 kg to 69.82 kg before rising to 74.29 after the war.
The authors, who emphasise that the finding needs to be confirmed in the mothers of testicular cancer patients in a case-control study, say that insulin may be the link between increased body mass and the corresponding increased incidence of the cancer. Overweight is associated with increased levels of insulin which leads to increased levels of free oestrogen that can be transferred across the placenta.
"Our results show an ecologic correlation between maternal weight and the incidence of testicular cancer among males born in 1931-55. Both variables displayed a transient drop during the second world war. Although one cannot draw firm conclusions from ecologic correlations, and no causal or quantitative relationships can be truly inferred, our findings may potentially be explained by lower insulin levels and thereby increased sex hormone binding globulin levels during pregnancy," say the authors.(Abergavenny Roger Dobson)
During the war, when energy intake and weight went down, so too did the incidence of testicular cancer, according to the results of the research in the International Journal of Cancer (2005;116:327-30).
"Our results further support the notion that testicular cancer is an example of a civilisation disease associated with a Westernised lifestyle with increase in obesity, obesity associated cancer forms, and diabetes type 2," say the authors, from the Cancer Registry of Norway, Oslo University College, and Rikshospitalet University Hospital.
Since the 1950s, the incidence of testicular cancer in the West has increased, and a number of theories have been suggested for this, from chemicals in the environment, to fetal exposure, to increased levels of oestrogen.
"It has been discussed for a long time whether exogenous endocrine disrupters may affect the pregnant mother and her offspring, but the use of the vast majority of manmade chemicals started to expand after . Since most of the men developing testicular cancer are 20 to 45 years old, it is reasonable to look for changes in natural risk factors taking place as early as 1920-30 to explain the increased incidence of testicular cancer since the 1950s onward," say the authors.
The aim of the study was to investigate whether maternal weight was associated with the incidence of testicular cancer using a unique Norwegian database that includes men born around the time of the second world war when the nutritional conditions changed due partly to a 15%-20% energy restriction imposed on the Norwegian population.
In the study, the authors compared data for a random sample of women giving birth in Oslo, Norway, in 1931-55 with the cancer incidence among men born in the whole country in the same period. The first 10 women a month to meet all criteria were included in the study, making 120 women a year and 3000 in total. Among all men born in Norway, all the 1790 patients with testicular cancer who were born 1931-55 and those diagnosed at the ages of 21 to 45 years were included.
The results show that the rates of testicular cancer among those born in the war years did drop. The rate in the period 1936 to 1940 was 10.3 per 100 000 person year, dropping to 8.7 in the 1941 to 1945 period, and then rising again to 11.6 in the five years after the war. In the same periods, the average maternal weight of women giving birth in Oslo dropped from 72.28 kg to 69.82 kg before rising to 74.29 after the war.
The authors, who emphasise that the finding needs to be confirmed in the mothers of testicular cancer patients in a case-control study, say that insulin may be the link between increased body mass and the corresponding increased incidence of the cancer. Overweight is associated with increased levels of insulin which leads to increased levels of free oestrogen that can be transferred across the placenta.
"Our results show an ecologic correlation between maternal weight and the incidence of testicular cancer among males born in 1931-55. Both variables displayed a transient drop during the second world war. Although one cannot draw firm conclusions from ecologic correlations, and no causal or quantitative relationships can be truly inferred, our findings may potentially be explained by lower insulin levels and thereby increased sex hormone binding globulin levels during pregnancy," say the authors.(Abergavenny Roger Dobson)