Pesticides and Non-Hodgkins Lymphoma
News Release: 2 July 1999

A case-control study of Non-Hodgkins Lymphoma (NHL) based on 442 cases and twice the number of controls was carried out in Sweden. Exposure was assessed by questionnaire.

It had been thought that exposure to 2,4,5-T (contaminated with TCDD dioxin) was a risk factor in NHL. However, 2,4,5-T was banned in Sweden in 1977. It now seems that the phenoxy herbicide MCPA may be a risk factor.

Increased risk was found for subjects exposed to herbicides. Within the herbicide group, phenoxy herbicides were associated with most risk, and MCPA within this group had the most significant increased risk. For several categories of herbicide, only exposure during the most recent decades before diagnosis of NHL was associated with an increased risk of NHL

Apart from the statistics, two other features suggest this. Firstly, the rise in NHL parallels the first and subsequent use of MCPA. Also, immunosuppression is a risk factor for NHL and immunotoxic effects are reported for MCPA.

Glyphosate exposure carried an increased risk apparently (but only 4 cases examined). Gene mutations and chromosomal aberrations have been reported in mouse lymphoma cells exposed to glyphosate. Subjects exposed to glyphosate (and other pesticides) have an increased risk of hairy cell leukaemia, a rare type of NHL. Glyphosate deserves further study.

Exposure to organic solvents did not increase risk of NHL.

Case control study of Non-Hodgkins Lymphoma and Exposure to Pesticides
L Hardell, M Eriksson. Cancer (Jo. Am. Canc. Soc. (?)) vol 6 (15) March 1999, 1353-1360.