Where are we at with lead? Current levels, time trend, and determinants of blood lead in New Zealand children and adults

A national biomonitoring survey was conducted in 2014–2016, to determine current blood lead levels (BLL) in New Zealand children and adults and identify determinants of BLL. Blood samples were provided by 191 children (age 5–18) and 304 adults (age 20–65) and analysed for BLL using inductively coupled mass spectroscopy. Linear regression on log-transformed BLL was used to assess associations between BLL and demographic and lifestyle factors collected via questionnaire. The geometric mean (GM) BLL was 0.86 μg/dl (95%CI 0.80–0.92) for children and 1.31 μg/dl (1.23–1.39) for adults, representing a 90% reduction in BLL over the past 36 years. For children, shellfish consumption was associated with 20% higher BLL. Adult BLLs were positively associated with age, beer consumption, spirits consumption, having roof water as the home's water supply, and having worked in glass manufacturing. Determinants of reduced BLL were tofu and canned food consumption. For women, menopause was associated with 34% higher BLL. Although significant reductions in New Zealanders’ BLL have been achieved in the past decades, this study identified several additional opportunities to reduce further background exposure to lead. In particular, consideration needs to be given to reducing lead levels in New Zealand roof water supplies.