Table 3.
Multivariable-adjusted relative risk (95% confidence interval) of primary open-angle glaucoma subtypes defined by intraocular pressurea, by deciles of low-carbohydrate-diet scores,b using pooled data (Nurses’ Health Study: 1980–2016, Health Professionals Follow-up Study: 1986–2016, Nurses’ Health Study II: 1991–2017).
| Subtype of POAG | Deciles of scores of adherence to a low-carbohydrate-diet | |||||||
|---|---|---|---|---|---|---|---|---|
| Decile 1 | Decile 3 | Decile 5 | Decile 7 | Decile 10 | Ptrend | Per 1 unit increase in adherence score | Pheterogeneityc | |
| Overall low-carbohydrate-diet score | ||||||||
| High-tension glaucoma (intraocular pressure ≥ 22 mmHg) | 0.06 | |||||||
| Cases (total n = 1370) | 107 | 120 | 159 | 137 | 126 | |||
| Multivariable-adjusted RR (95% CI)d | 1 (referent) | 1.18 (0.91, 1.54) | 1.40 (1.08, 1.79) | 1.27 (0.98, 1.64) | 1.31 (1.00, 1.72) | 0.08 | 1.02 (1.00, 1.04) | |
| Normal-tension glaucoma (intraocular pressure < 22 mmHg) | ||||||||
| Cases (total n = 742) | 82 | 73 | 82 | 62 | 50 | |||
| Multivariable-adjusted RR (95% CI)d | 1 (referent) | 0.78 (0.57, 1.08) | 0.84 (0.61, 1.15) | 0.73 (0.52, 1.02) | 0.87 (0.61, 1.26) | 0.30 | 0.99 (0.96, 1.01) | |
| Animal-based low-carbohydrate-diet score | ||||||||
| High-tension glaucoma (intraocular pressure ≥ 22 mmHg) | 0.07 | |||||||
| Cases (total n = 1370) | 118 | 134 | 171 | 125 | 130 | |||
| Multivariable RR (95% CI)d | 1 (referent) | 1.03 (0.80, 1.32) | 1.36 (1.06, 1.73) | 1.06 (0.82, 1.38) | 1.24 (0.95, 1.61) | 0.08 | 1.02 (1.00, 1.04) | |
| Normal-tension glaucoma (intraocular pressure < 22 mmHg) | ||||||||
| Cases (total n = 742) | 86 | 79 | 73 | 61 | 52 | |||
| Multivariable RR (95% CI)d | 1 (referent) | 0.78 (0.57, 1.07) | 0.72 (0.52, 1.00) | 0.69 (0.49, 0.97) | 0.89 (0.62, 1.28) | 0.34 | 0.99 (0.96, 1.02) | |
| Vegetable-based low-carbohydrate-diet score | ||||||||
| High-tension glaucoma (intraocular pressure ≥ 22 mmHg) | 0.47 | |||||||
| Cases (total n = 1370) | 138 | 117 | 126 | 143 | 137 | |||
| Multivariable RR (95% CI)d | 1 (referent) | 0.84 (0.65, 1.08) | 0.89 (0.69, 1.14) | 0.93 (0.73, 1.18) | 0.99 (0.78, 1.26) | 0.57 | 1.01 (0.99, 1.03) | |
| Normal-tension glaucoma (intraocular pressure < 22 mmHg) | ||||||||
| Cases (total n = 742) | 70 | 80 | 66 | 82 | 61 | |||
| Multivariable RR (95% CI)d | 1 (referent) | 0.98 (0.71, 1.36) | 0.83 (0.59, 1.17) | 0.95 (0.68, 1.32) | 0.91 (0.64, 1.30) | 0.63 | 1.00 (0.97, 1.02) | |
CI confidence interval, HPFS Health Professionals Follow-up Study, NHS Nurses’ Health Study, POAG primary open-angle glaucoma, RR relative risk.
aBased on maximum untreated intraocular pressure at diagnosis.
bDiet scores were based on cumulatively averaged intakes of macro nutrients (i.e. average of all available intake data from food frequency questionnaires completed before each 2-year period at risk); because diabetes may be an intermediate factor in the aetiology, diet was no longer updated after a diabetes diagnosis.
cFor testing whether the associations between low-carbohydrate-diet scores and one POAG subtype is significantly different from that with another subtype, we used the Lunn–McNeil approach to test for heterogeneity in associations and derived the p for heterogeneity.
dAll multivariable-adjusted analyses included the same set of covariates as described in footnoteb in Table 2.