Moulds, bacteria and cancer among Finns: an occupational cohort study

Abstract

Exposures at the investigated concentrations to either moulds or bacteria are unlikely to be major risk factors of cancer, although suggestions of risk increases were observed for some cancer types. It has been suggested previously that the decreased risk for lung cancer is due to the protective effect of endotoxins.

Endotoxin and Cancer

“…Pesticides were the principal focus of that study; endotoxin has not yet been investigated as a possible explanatory factor for the lung cancer deficit. A deficit in lung cancer risk was also observed in a study of more than a million Finnish men based on their self-reported longest held occupation in the 1970 national census, lagged by 20 years, with endotoxin exposure determined by an occupational exposure matrix (Laakkonen et al 2008); a deficit was not observed in women. In contrast, a study of occupational exposures in Leningrad Province, Russia, reported a > 2-fold greater risk of lung cancer in subjects ever occupationally exposed to cotton dust (Baccarelli et al 2006).…”

“…Other cancer end points have been studied, including cancers of the liver, esophagus, stomach, rectum, pancreas, breast, brain, ovary, thyroid, and nasopharynx, but not as extensively as the lung, and the findings have been inconsistent (Chang et al 2006; De Roos et al 2005; Gold et al 2006; Henderson and Enterline 1973; Hodgson and Jones 1990; Kuzmickiene et al 2004; Laakkonen et al 2008; Li et al 2006a; Mastrangelo et al 2008; Merchant and Ortmeyer 1981; Ray et al 2007; Stark et al 1990; Szeszenia-Dabrowska et al 1999; Wang et al 2002; Wernli et al 2003, 2006, 2008; Wong et al 2006). Nonetheless, subsequent effects in other organ systems are plausible because cells with TLR4 receptors are widely disseminated, and elevation of systemic inflammatory mediators, including TNF-α, IL-1, IL-6, and IL-8, has been shown after inhalation of LPS or media contaminated with endotoxin (Hodgson 2006; Larsson et al 1994; Mackensen et al 1992; Mattsby and Rylander 1978; Michel et al 1997; Palmberg et al 2002; Reisser et al 2002).…”

Lung cancer risk and occupational exposures in crop farming: results from the AGRIculture and CANcer (AGRICAN) cohort

“…However, there is very little data on associations between mould exposure and lung cancer. Using data from the Finnish job exposure matrix, Laakkonen et al 35 reported a decreased risk of lung cancer among men exposed to high levels of moulds, when adjusting on group-level data for smoking. However, mould and bacterial exposure, including endotoxins that might be protective against lung cancer, were strongly correlated.…”

Microbial deprivation, inflammation and cancer

“…Cotton textile workers are less likely to develop lung cancers as compared to the general populations [31], and one study suggests that this may also be the case for sewage plant workers [32]. A study on all economically active Finns identified in a population census in 1970, followed for 30 million-person years, revealed that heavy exposure to moulds and bacteria in the working environment was associated with reduced lung cancer risk among men [33]. These epidemiological data need, however, be viewed with caution, because many other factors than exposure to microbes could also be involved and partly explain the statistical associations observed, such as the diet, exercise or exposure to the sunlight, thus confirmatory studies are needed.…”

“…Accumulating data obtained from several lines of evidence suggest that cancers occur less frequently 1. Among people who are, by occupation, heavily exposed to environmental micro-organisms [25][26][27][28][29][30][31][32][33] 2. Among populations that adhere to a traditional lifestyle [34] 3.…”