Table 4. Estimated mean difference in serum LDL cholesterol (mg/dL) and dietary cholesterol (mg/1,000 kcal) higher by 1 SD^* by education years and sequential regression models in the INTERLIPID study in Japan, 1996–1999.

Model	Men (n = 533)				Women (n = 506)
	LDL-C (mg/dL)	95% CI		P value	LDL-C (mg/dL)	95% CI		P value
Unadjusted	−3.16	−5.52	−0.79	0.009	−1.64	−4.30	+1.02	0.226
Model 1
≥ 12 years	−4.83	−7.44	−2.22	< 0.001	−0.52	−3.77	+2.73	0.754
<12 years	+2.77	−2.78	+8.31	0.328	−2.57	−6.88	+1.75	0.243
Model 2
≥ 12 years	−3.65	−6.24	−1.06	0.006	+0.85	−2.55	+4.26	0.622
<12 years	+4.40	−1.03	+9.84	0.112	−2.81	−7.13	+1.51	0.202
Model 3
≥ 12 years	−3.66	−6.25	−1.07	0.006	+0.75	−2.67	+4.17	0.668
<12 years	+4.46	−0.97	+9.90	0.107	−2.82	−7.14	+1.50	0.200

^*1 SD difference for dietary cholesterol is 67.5 mg/1,000 kcal for men and 65.9 mg/1,000 kcal for women. Coefficients for dietary cholesterol were based on the use of indicator variables for education years. Tests were also performed to clarify whether the coefficients differed between the education years of ≥ 12 and < 12 years.

Model 1 = dietary cholesterol + education years (≥ 12 /< 12 years) + dietary cholesterol × education years

Model 2 = Model 1 + age, BMI, menopausal status in women (before/in the middle or after), number of cigarettes, alcohol intake, SFA, PUFA, MUFA, TFA, soluble fiber, and site

Model 3 = Model 2 + employment status (“employed in a company”/ “the others”)

P values for the interaction term between dietary cholesterol and education years (dietary cholesterol × education years) are as follows: P = 0.015 for men and P = 0.457 for women in Model 1, P = 0.007 for men and P = 0.162 for women in Model 2, and P = 0.007 for men and P = 0.174 for women in Model 3.