Table 3.
Cross-sectional associations between phthalate biomarkers and bone mineral density measures, stratified by hormone therapy use, N = 1229
| Total hip BMD, 1000 × g/cm2 | Femoral neck BMD, 1000 × g/cm2 | |||||
|---|---|---|---|---|---|---|
| Phthalate biomarker | No HTa use N = 457 | HTa use N = 772 | No HTa use N = 457 | HTa use N = 772 | ||
| β (95% CI)b | β (95% CI)b | P interaction | β (95% CI)b | β (95% CI)b | P interaction | |
| MEP, ng/mL | ||||||
| 0.8-31.8 | Ref | Ref | .71 | Ref | Ref | .43 |
| 31.9-67.9 | –4.58 (–10.44 to 1.28) | –0.55 (–5.30 to 4.19) | 3.70 (–3.28 to 10.69) | 1.21 (–4.74 to 7.16) | ||
| 68.0-163.0 | –5.22 (–11.47 to 1.03) | –5.04 (–10.37 to 0.30) | –0.13 (–7.56 to 7.30) | 1.63 (–5.03 to 8.30) | ||
| 164.0-26 000 | –1.99 (–9.37 to 5.38) | –0.71 (–6.43 to 5.01) | 1.80 (–6.94 to 10.54) | 6.66 (–0.47 to 13.79) | ||
| P trend | .63 | .59 | .98 | .07 | ||
| MBzP, ng/mL | ||||||
| 0.2-5.9 | Ref | Ref | .58 | Ref | Ref | .90 |
| 6.0-11.8 | –0.14 (–5.67 to 5.40) | 4.84 (0.18 to 9.50) | 4.33 (–2.31 to 10.96) | 5.87 (0.03 to 11.71) | ||
| 11.9-22.0 | –5.52 (–11.47 to 0.43) | –0.44 (–5.58 to 4.69) | –1.50 (–8.62 to 5.61) | 1.80 (–4.62 to 8.22) | ||
| 22.1-3590.0 | –4.94 (–12.42 to 2.54) | –1.13 (–7.21 to 4.95) | –0.53 (–9.45 to 8.38) | 1.34 (–6.23 to 8.92) | ||
| P trend | .07 | 0.42 | .57 | .96 | ||
| MCOP, ng/mL | ||||||
| 0.1-2.1 | Ref | Ref | .75 | Ref | Ref | .57 |
| 2.2-3.6 | 1.03 (–4.20 to 6.27) | 2.73 (–2.10 to 7.55) | –1.52 (–7.79 to 4.76) | 1.28 (–4.78 to 7.34) | ||
| 3.7-6.5 | –2.19 (–7.97 to 3.59) | 1.30 (–3.76 to 6.36) | –6.11 (–13.02 to 0.80) | –0.53 (–6.87 to 5.81) | ||
| 6.6-270.0 | –0.68 (–7.42 to 6.06) | 0.93 (–4.72 to 6.57) | –2.43 (–10.49 to 5.62) | –0.72 (–7.80 to 6.36) | ||
| P trend | .61 | 0.90 | .32 | .72 | ||
| MCNP, ng/mL | ||||||
| 0.1-1.6 | Ref | Ref | .40 | Ref | Ref | .96 |
| 1.7-2.6 | –0.11 (–5.49 to 5.26) | 1.99 (–2.74 to 6.71) | 2.22 (–4.30 to 8.74) | 0.58 (–5.33 to 6.50) | ||
| 2.7-4.7 | –2.94 (–8.95 to 3.07) | 1.06 (–4.09 to 6.21) | 0.30 (–6.97 to 7.57) | –1.45 (–7.89 to 4.99) | ||
| 4.8-222.0 | 4.12 (–2.52 to 10.75) | 1.44 (–4.04 to 6.92) | 1.52 (–6.50 to 9.54) | 0.83 (–6.02 to 7.67) | ||
| P trend | .38 | .74 | .85 | .97 | ||
| MCPP, ng/mL | ||||||
| 0.1–1.7 | Ref | Ref | .03 | Ref | Ref | .01 |
| 1.8-3.0 | –4.77 (–10.35 to 0.82) | 3.87 (–0.79 to 8.53) | -4.71 (–11.35 to 1.93) | 0.76 (–5.10 to 6.61) | ||
| 3.1-5.4 | –8.22 (–14.19 to –2.24) | 4.33 (–0.61 to 9.28) | –11.22 (–18.31 to –4.12) | 4.34 (–1.87 to 10.56) | ||
| 5.5-124.0 | –6.90 (–14.32 to 0.52) | 1.10 (–4.88 to 7.09) | –7.37 (–16.16 to 1.42) | –0.63 (–8.12 to 6.86) | ||
| P trend | .03 | .58 | .03 | .77 | ||
| ∑DBP, µmol/L | ||||||
| 0.002-0.056 | Ref | Ref | .17 | Ref | Ref | .60 |
| 0.06-0.1 | 3.69 (–1.70 to 9.07) | –1.46 (–6.31 to 3.39) | 1.61 (–4.85 to 8.06) | –1.55 (–7.62 to 4.52) | ||
| 0.1-0.2 | –1.71 (–7.58 to 4.15) | –1.12 (–6.41 to 4.16) | –1.53 (–8.56 to 5.49) | 0.90 (–5.69 to 7.49) | ||
| 0.2-28.2 | 1.18 (–6.22 to 8.59) | –5.40 (–11.60 to 0.80) | –2.93 (–11.76 to 5.90) | –0.56 (–8.27 to 7.14) | ||
| P trend | .85 | .13 | .45 | .95 | ||
| ∑DiBP, µmol/L | ||||||
| 0.002-0.006 | Ref | Ref | .01 | Ref | Ref | .12 |
| 0.006-0.01 | –2.88 (–8.22 to 2.46) | 5.37 (0.56 to 10.19) | –1.24 (–7.65 to 5.17) | –1.44 (–7.43 to 4.55) | ||
| 0.01-0.03 | –3.57 (–9.62 to 2.48) | 5.53 (0.09 to 10.97) | –2.83 (–10.06 to 4.41) | 2.61 (–4.12 to 9.34) | ||
| 0.03-4.0 | –11.09 (–18.69 to –3.49) | 4.77 (–1.81 to 11.35) | –5.48 (–14.53 to 3.56) | 5.19 (–2.91 to 13.30) | ||
| P trend | .01 | .15 | .24 | .16 | ||
| ∑DEHP, µmol/L | ||||||
| 0.08-0.1 | Ref | Ref | .49 | Ref | Ref | .74 |
| 0.1-0.2 | –4.83 (–10.56 to 0.90) | –0.68 (–5.42 to 4.06) | –2.88 (–9.77 to 4.02) | 0.37 (–5.58 to 6.31) | ||
| 0.2-0.3 | –0.52 (–6.64 to 5.59) | 2.81 (–2.24 to 7.86) | –2.11 (–9.46 to 5.24) | 2.13 (–4.20 to 8.47) | ||
| 0.3-68.5 | 0.10 (–6.58 to 6.78) | –1.80 (–7.59 to 3.98) | –0.47 (–8.50 to 7.55) | 2.04 (–5.20 to 9.28) | ||
| P trend | .70 | .89 | .98 | .49 | ||
Abbreviations: BMD, bone mineral density; DBP, di-n-butyl phthalate; DEHP, di(2-ethylhexyl) phthalate; DiBP, di-isobutyl phthalate; HT, hormone therapy; MBzP, monobenzyl phthalate; MCNP, monocarboxyisononyl phthalate; MCOP, monocarboxyisooctyl phthalate; MCPP, mono-3-carboxypropyl phthalate; MEP, monoethyl phthalate; Ref, reference.
a HT use includes both reported medication use as well as HT intervention assignment, where appropriate. “Never” is defined as no reported HT use at baseline and also no HT use at year 3; “ever” includes reported past or current HT use at baseline and/or year 3.
b Adjusted for creatinine, age, race/site, smoking status, and body mass index; scaled by a factor of 1000.