EHINZ has recently published two factsheets that look at occupational and non-occupational notifications entered via the Hazardous Substances Disease and Injury Reporting Tool (HSDIRT) between 2014 and 2021. The notification rates have increased by almost double in 2021 both within and outside of workplace exposure, primarily due to lowering the blood lead levels requiring notification from 0.48 µmol/L to 0.24 µmol/L.
The occupational lead absorption factsheet reported on the data of individuals potentially exposed in the workplace and showed that between 2020 and 2021, the lead notification rates for Pacific peoples were four times greater than any other ethnic group. Pacific peoples also had the highest median blood lead levels at 0.68 µmol/L, continuing a trend from previous years, with European/Other coming next at 0.58, Asian at 0.56 and Māori at 0.52.
Painters have been the most notified career group for high blood lead levels every year since 2014, accounting for half of all notifications. The data also showed that within that timeframe, notification rates are higher in older working-age men, with males making up 95 per cent of occupational lead notifications where gender is recorded.
The non-occupational data revealed that since 2014, lead-based paint and indoor rifle ranges are the most commonly known and recorded exposure sources. Lead-based paint is responsible for over a third of non-occupational lead notifications and results in the second highest median blood lead level at 0.69 µmol/L. The origin of the lead exposure was unknown for roughly one third of all non-occupational cases.
Between 2017 and 2021, males aged 45-73 had the highest non-occupational lead notification rates, making up roughly half of all notifications.
During this timeframe, lead notifications from non-occupational/unknown sources were highest in European /Other at 1.8 per 100,000, followed by Pacific peoples at 1.7 per 100,000. The rate was predominantly due to the Housing New Zealand Study, a mass testing event performed in Auckland in 2018, that assessed people involved with public housing and identified a large number of Pacific peoples as having high blood lead levels. This suggests many unidentified cases are out there and may disproportionately include Pacific peoples and those of low socioeconomic status.
Author of the factsheets, Intelligence Analyst Liam Kelly, says the data extracted doesn’t represent the total burden of the disease.
“Between 2020 to 2021, there was a high amount of missing data which was partly due to the public health services focusing on the COVID-19 pandemic and the restrictions reducing access to blood testing. However, many cases may go undetected as often there are no symptoms at lower blood levels, making awareness around potential exposure imperative.”
He says that seeing the notification rates double with the change in notification levels shows that lead absorption remains a significant and insufficiently acknowledged public health issue within Aotearoa New Zealand.
“The lowering of notifiable blood lead levels occurred because more evidence has been found that levels below 0.48 µmol/L can cause health effects that can be irreversible. We are now seeing higher notification rates of lead absorption as a result.”
There is no safe level of exposure, with the range and severity of symptoms becoming more prominent as the level of lead in the blood increases. Symptoms can include high blood pressure, kidney damage and pregnancy complications in adults, and affected development in the brain and nervous system of children.
HSDIRT is an electronic reporting system developed by EHINZ that has operated since 2013. It is designed for general practitioners to notify cases of disease and injuries related to lead and other hazardous substances.
EHINZ, based within Massey University’s College of Health, is funded by the Ministry of Health to monitor and provide intelligence on the effect of the environment on the health of New Zealanders.
Read the full lead absorption notification factsheets here: Occupational | Non-occupational
Liam Kelly, Intelligence Analyst with EHINZ.
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