Background: There is strong evidence that mineral oil hydrocarbons are the greatest contaminant of the human body, amounting to approximately 1 g per person. Possible routes of contamination include air inhalation, food intake, and dermal absorption. The present study aims to identify the most relevant sources of mineral oil contamination.
Methods: One hundred forty-two women undergoing elective cesarean section were enrolled. A specimen of subcutaneous fat was removed prior to wound closure. On days 4 and 20 postpartum, milk samples were collected from the women. Fat and milk samples were analyzed for mineral oil saturated hydrocarbons (MOSH). All women completed a questionnaire on personal data, nutrition habits, and use of cosmetics. MOSH concentrations in fat tissue were compared with data from the questionnaire and with MOSH concentrations in corresponding milk samples.
Results: The predominant predictor for MOSH contamination of fat tissue was age (p<0.001). Furthermore, body mass index (p=0.001), country of main residence (p=0.03), number of previous childbirths (p=0.029), use of sun creams in the present pregnancy (p=0.002), and use of hand creams and lipsticks in daily life (p=0.011 and p=0.007, respectively) were significant independent determinants. No association was found with nutritional habits. A strong correlation was seen between MOSH concentration in fat tissue (median 52.5 mg/kg) and in the corresponding milk fat sample from day 4 (median 30 mg/kg) (p<0.001) and day 20 (median 10 mg/kg) (p=0.028).
Conclusions: The increase in MOSH concentration in human fat tissue with age suggests an accumulation over time. Cosmetics might be a relevant source of the contamination.