An assessment of compliance with optimal fluoride levels for oral health benefit by New Zealand drinking water suppliers.

OBJECTIVES: Community water fluoridation (CWF) has proven oral health benefits. We investigated whether drinking water suppliers are meeting New Zealand CWF targets (0.7-1.0 ppm) to ensure these benefits. METHODS: We retrieved fluoride testing data from 25 supplies serving 2,059,000 people (82% of people on a fluoridated supply), for the years 1992-2022 (22,220 weekly observations). We descriptively assessed compliance with fluoride targets in this convenience sample. RESULTS: The mean fluoride level was 0.66 ppm (SD 0.28). Water suppliers achieved fluoride targets 54.1% of the time (range 4.2%-77.9%). Fluoride concentration fell short of the target in 42.2% of observations, exceeded but under the maximum acceptable value (MAV) in 3.6%, and in excess of the MAV in 0.1%. The percentage of compliant observations was greater in larger than smaller supplies. CONCLUSIONS: Noncompliance with CWF targets was common. Epidemiological studies that rely on fluoridation status as their exposure may underestimate the oral health benefits of CWF. Our results highlight future challenges with the feasibility of expanding CWF under new legislation as well as the weaknesses in drinking water surveillance.

Mental health inequities for Maori youth: a population-level study of mental health service data.

AIM: To examine specialist mental health service, hospital discharge, and pharmaceutical dispensing data for emotional conditions (anxiety, depression), substance use, and self-harm for Maori compared to non-Maori/non-Pasifika (NMNP) youth. METHODS: A novel population-level case identification method using New Zealand's Integrated Data Infrastructure for 232,845 Maori and 627,891 NMNP aged 10-24 years. Descriptive statistics on mental health conditions were generated and stratified by Maori/NMNP. Unadjusted and adjusted risk ratios (RRs) of mental health conditions were generated using generalised linear regression. RESULTS: Maori were less likely to be identified for anxiety (ARR=0.88; 95% CI 0.85-0.90) or depression (ARR=0.92; 95% CI 0.90-0.95) than NMNP. They were more likely to be identified for substance problems (ARR)=2.66; 95% CI 2.60-2.71) and self-harm (ARR=1.56; 95% CI 1.50-1.63). Maori living in high deprivation areas were significantly more likely to be identified for substance problems, but less likely for emotional conditions, than Maori in least deprived areas. CONCLUSION: Despite known high levels of mental health concerns for rangatahi Maori, administrative data suggests significant under-reporting, assessment, and treatment of emotional conditions relative to NMNP. These differences were exacerbated by deprivation. Maori were more likely to be referred to services for externalised symptoms of distress (substance use and self-harm).