Exploration of Medicine

Table 2. Country-specific and pooled regression coefficients for water quality indicators and CKD burden.

Outcome	Predictor	Country	Beta	95% CI	SE	P_value	N	Std beta
DALYs	Nitrate	China	–1.326	–14.0660–11.4150	6.5	0.8384	8	–0.00
DALYs	Nitrate	Canada	5.752	–13.7910–25.2950	9.971	0.564	8	2.18
DALYs	Nitrate	Ireland	–12.104	–19.7990 to –4.4080	3.926	0.0021	8	–0.25
DALYs	Nitrate	Pooled	–5.128	–15.3690–5.1130	5.225	0.3263	24	–0.41
DALYs	Nitrogen	China	–0.338	–5.4020–4.7250	2.583	0.8958	8	–0.00
DALYs	Nitrogen	Canada	–5.828	–21.6030–9.9460	8.048	0.469	8	–0.14
DALYs	Nitrogen	Ireland	–4.695	–8.9130 to –0.4770	2.152	0.0291	8	–0.02
DALYs	Nitrogen	Pooled	–3.028	–6.2030–0.1460	1.62	0.0615	24	–0.05
DALYs	Temperature	China	0.888	–11.9500–13.7260	6.55	0.8922	8	0.02
DALYs	Temperature	Canada	2.925	–22.9750–28.8250	13.214	0.8248	8	0.53
DALYs	Temperature	Ireland	–4.148	–19.5850–11.2900	7.876	0.5985	8	–0.14
DALYs	Temperature	Pooled	–0.651	–9.8750–8.5720	4.706	0.8899	24	–0.09
Deaths	Nitrate	China	–0.037	–0.5930–0.5190	0.284	0.8955	8	–0.00
Deaths	Nitrate	Canada	0.323	–0.7790–1.4250	0.562	0.5654	8	2.53
Deaths	Nitrate	Ireland	–0.942	–1.6070 to –0.2770	0.339	0.0055	8	–0.26
Deaths	Nitrate	Pooled	–0.281	–1.0000–0.4370	0.367	0.4428	24	–1.26
Incidence	Nitrogen	China	–0.005	–0.0600–0.0490	0.028	0.8476	8	–0.00
Incidence	Nitrogen	Canada	–0.631	–1.0760 to –0.1860	0.227	0.0055	8	–0.20
Incidence	Nitrogen	Ireland	0.077	–0.0460–0.1990	0.062	0.219	8	0.01
Incidence	Nitrogen	Pooled	–0.046	–0.2200–0.1290	0.089	0.6066	24	–0.00

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Standardized beta is expressed per 1-SD higher water-quality indicator. SE: standard error.

Declarations

Author contributions

TR: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Software, Visualization, Writing—original draft, Writing—review & editing. ZZ: Conceptualization, Investigation, Methodology, Validation, Writing—review & editing. TR and ZZ contributed equally to this work. Both authors read and approved the submitted version.

Conflicts of interest

The authors declare that there are no conflicts of interest.

Ethical approval

This study used publicly available, de-identified aggregate data. No ethical review was required.

Consent to participate

Not applicable.

Consent to publication

Not applicable.

Availability of data and materials

The CKD burden data analyzed in this study were obtained from the Institute for Health Metrics and Evaluation (IHME) GBD Results Tool (https://vizhub.healthdata.org/gbd-results/), subject to IHME data-use terms. The downloaded IHME citation identified the release as Global Burden of Disease Study 2023 (GBD 2023) Results, and the present analysis was restricted to country-year estimates from 2010 to 2017. Water quality data were obtained from public monitoring sources in China, Canada, and Ireland, as documented in the source file. Derived datasets and analysis code are available from the corresponding author upon reasonable request.

Funding

This work was supported by the Yunnan Provincial Department of Education Science Research Fund (grant numbers 2026J2256 and 2024J2133). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Copyright

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