The associations of daylight and melatonin receptor 1B gene rs10830963 variant with glycemic traits: the prospective PPP-Botnia study

Figures & data

Table 1. Sample characteristics.

Variable	Whole sample at baseline N (%) or Mean (SD)	p whole sample versus analytic sample at baseline	Analytic sample baseline visit N (%) or mean (SD)	Analytic sample follow-up N (%) or mean (SD)	p whole sample at baseline versus analytic sample at follow-up	Analytic sample change over time Mean difference (SD) or %	p analytic sample change over time
Sex					NA		NA
Men	2253 (46.1%)		1577 (46.1%)	1577 (46.1%)		NA
Women	2631 (53.9%)		1845 (53.9%)	1845 (53.9%)		NA
Age (years)	48.75 (15.56)	NA	48.97 (14.71)	55.26 (14.60)	NA	6.29 (0.98)	NA
BMI (kg/m^2)	26.28 (4.30)	NA	26.24 (4.20)	26.78 (4.37)	NA	0.54 (2.04)	NA
S-insulin (mmol/l)
Fasting	6.72 (5.78)	.811	6.66 (5.71)	7.66 (5.76)	<.001	1.13 (4.56)	<.001
30 min	59.27 (37.63)	.316	58.62 (37.73)	67.84 (47.31)	<.001	9.00 (34.34)	<.001
120 min	32.93 (33.49)	.234	32.04 (32.45)	39.05 (44.51)	<.001	6.22 (29.42)	<.001
AUC^a	5147.85 (3309.31)	.227	5078.44 (3242.26)	5968.86 (4294.92)	<.001	848.71 (2857.26)	<.001
P-glucose(mU/l)
Fasting	5.27 (0.56)	.782	5.27 (0.56)	5.39 (0.73)	<.001	0.11 (0.67)	<.001
30 min	8.28 (1.62)	.214	8.24 (1.60)	8.45 (1.73)	<.001	0.20 (1.54)	<.001
120 min	5.23 (1.57)	.042	5.18 (1.53)	5.55 (1.99)	<.001	0.36 (1.73)	<.001
AUC^a	811.08 (142.29)	.048	806.32 (138.52)	837.47 (171.79)	<.001	29.85 (140.48)	<.001
Insulin sensitivity
HOMA-IR	1.61 (1.73)	.853	1.60 (1.82)	1.89 (1.66)	<.001	0.33 (1.24)	<.001
ISI	9.25 (5.63)	.257	9.36 (5.77)	8.18 (5.58)	<.001	−1.21 (4.76)	<.001
Insulin secretion
DI	1782.27 (2331.73)	.784	1771.09 (2292.83)	1664.44 (2390.74)	<.001	−117.83 (2745.67)	<.001
CIR	195.17 (180.35)	.571	193.31 (171.82)	213.07 (279.80)	<.001	20.89 (181.57)	<.001
Daylight
Average day length in hours	10.97 (4.42)	NA	10.95 (4.40)	11.81 (4.56)	NA	0.85 (6.50)	NA
Smoking	NA			NA		NA
No or former			2880 (86.7%)	2990 (90.0%)
Yes			442 (13.3%)	332 (10.0%)
Alcohol consumption (doses/week)	NA			NA		NA
None			228 (9.0%)	401 (14.7%)		5.7%
1–4			1446 (57.1%)	1558 (57.2%)		0.1%
5–10			563 (22.2%)	545 (20.0%)		−2.2%
>10			294 (11.6%)	221 (8.1%)		−3.5%
Education	NA			NA
Basic or less or missing	1366 (28.9%)		897 (26.9%)	NA
Upper secondary	1861 (39.3%)		1381 (41.5%)	NA
Lower tertiary	757 (16.0%)		516 (15.5%)	NA
Upper tertiary	750 (15.8%)		537 (16.1%)	NA
Exercise	NA			NA		NA
No (less than 3 times a week)	2145 (44.9%)		1452 (44.9%)	1590 (49.1%)		4.2%
Yes (equal or more than 3 times a week)	2636 (55.1%)		1783 (55.1%)	1645 (50.9%)		−4,2%
MTNR1B rs10830963
CC	2227 (48.4%)	.566	1694 (49.5%)	1694 (49.5%)	NA	NA	NA
CG	1911 (41.6%)		1402 (41.0%)	1402 (41.0%)		NA
GG	460 (10.0%)		325 (9.5%)	325 (9.5%)		NA

^aArea under the curve.

Table 2. Associations between amount of daylight and glycemic traits.

Outcome	B (95% CI)	p^1	B (95% CI)	p^2
Baseline^a
Glucose
Fasting	0.026 (−0.007; 0.060)	.122	0.022 (−0.013; 0.057)	.224
AUC	0.030 (−0.003; 0.062)	.071	0.030 (−0.004; 0.064)	.086
Insulin
Fasting	0.022 (−0.008; 0.052)	.153	0.022 (−0.010; 0.054)	.171
AUC	0.002 (−0.030; 0.035)	.881	0.000 (−0.034; 0.034)	.999
Insulin sensitivity
HOMA	0.026 (−0.004; 0.056)	.095	0.025 (−0.007; 0.056)	.122
ISI	−0.015 (−0.046; 0.016)	.341	−0.013 (−0.046; 0.019)	.414
Insulin secretion
DI	−0.028 (−0.062; 0.005)	.096	−0.033 (−0.068; 0.002)	.062
CIR	−0.018 (−0.052; 0.017)	.309	−0.023 (−0.059; 0.013)	.202
Follow-up^a
Glucose
Fasting	−0.069 (−0.101; −0.037)	<.001	−0.069 (−0.103; −0.035)	<.001
AUC	0.053 (0.022; 0.084)	.001	0.061 (0.029; 0.094)	<.001
Insulin
Fasting	0.045 (0.016; 0.073)	.002	0.048 (0.018; 0.078)	.002
AUC	0.007 (−0.024; 0.038)	.645	0.010 (−0.022; 0.043)	.527
Insulin sensitivity
HOMA	0.028 (0.000; 0.056)	.052	0.031 (0.001; 0.0061)	.043
ISI	−0.023 (−0.051; 0.006)	.124	−0.027 (−0.057; 0.004)	<.001
Insulin secretion
DI	−0.048 (−0.080; −0.015)	.004	−0.052 (−0.086; −0.018)	.003
CIR	−0.040 (−0.073; −0.006)	.021	−0.040 (−0.076; −0.005)	.024
Change (follow-up – baseline)^a,^b
Glucose
Fasting	−0.017 (−0.047; 0.012)	.253	−0.027 (−0.058; 0.005)	.094
AUC	0.068 (0.036; 0.099)	<.001	0.062 (0.030; 0.095)	.000
Insulin
Fasting	0.000 (−0.030; 0.031)	.997	−0.002 (−0.034; 0.029)	.880
AUC	−0.010 (−0.042; 0.021)	.519	−0.012 (−0.045; 0.022)	.500
Insulin sensitivity
HOMA	−0.002 (−0.033; 0.029)	.897	−0.004 (−0.036; 0.029)	.818
ISI	−0.024 (−0.053; 0.005)	.104	−0.021 (−0.051; 0.010)	.185
Insulin secretion
DI	−0.030 (−0.064; 0.003)	.071	−0.033 (−0.069; 0.004)	.077
CIR	−0.037 (−0.071; −0.003)	.031	−0.039 (−0.075; −0.004)	.030

p¹ – linear regression models are adjusted for sex, age, BMI. Change models are adjusted for sex, baseline age and BMI, change between baseline and follow-up in age and BMI.

p² – linear regression models are adjusted for sex, age, BMI, smoking, alcohol use, physical activity at respective visit(s), and education at baseline. Change models are adjusted for sex, baseline age, BMI and education and change between baseline and follow-up in age and BMI and smoking, alcohol use and physical activity at both visits.

^a1SD compares to 4.50 h in day length at baseline visit and 4.56 hours at follow-up and 6.50 hours in change in day length.

^bChange in glycemic traits is predicted by change in daylight between baseline and follow-up.

B refers to one SD unit change in outcome per one SD unit change in daylight as a predictor.

Table 3. Associations between MTNR1B rs10830963 genotype and glycemic traits (additive model).

Outcome	B (95% CI)	p^1	B (95% CI)	p^2
Baseline
Glucose
Fasting	0.221 (0.171; 0.271)	<.001	0.216 (0.163; 0.269)	<.001
AUC	0.199 (0.151; 0.247)	<.001	0.207 (0.157; 0.258)	<.001
Insulin
Fasting	0.009 (−0.037; 0.055)	.698	−0.015 (−0.063; 0.032)	.528
AUC	−0.017 (−0.067; 0.032)	.503	−0.017 (−0.069; 0.034)	.510
Insulin sensitivity
HOMA	0.046 (0.000; 0.091)	.050	0.022 (−0.026; 0.069)	.377
ISI	−0.047 (−0.093; 0.000)	.050	−0.032 (−0.081; 0.017)	.199
Insulin secretion
DI	−0.248 (−0.298; −0.199)	<.001	−0.247 (−0.299; −0.195)	<.001
CIR	−0.224 (−0.275; −0.173)	<.001	−0.233 (−0.287; −0.179)	<.001
Follow-up
Glucose
Fasting	0.173 (0.124; 0.221)	<.001	0.158 (0.107; 0.208)	<.001
AUC	0.123 (0.076; 0.170)	<.001	0.121 (0.072; 0.171)	<.001
Insulin
Fasting	0.008 (−0.036; 0.051)	.723	0.009 (−0.037; 0.055)	.698
AUC	−0.043 (−0.090; 0.004)	.073	−0.038 (−0.087; 0.012)	.134
Insulin sensitivity
HOMA	0.041 (−0.002; 0.084)	.063	0.039 (−0.006; 0.084)	.091
ISI	−0.018 (−0.062; 0.025)	.397	−0.022 (−0.068; 0.024)	.358
Insulin secretion
DI	−0.192 (−0.241; −0.144)	<.001	−0.187 (−0.238; −0.136)	<.001
CIR	−0.213 (−0.253; −0.152)	<.001	−0.194 (−0.247; −0.141)	<.001
Change (follow-up – baseline)
Glucose
Fasting	0.088 (0.043; 0.134)	<.001	0.083 (0.036; 0.131)	.001
AUC	0.019 (−0.029; 0.067)	.438	0.017 (−0.033; 0.067)	.495
Insulin
Fasting	−0.001 (−0.047; 0.045)	.970	0.003 (−0.045; 0.051)	.893
AUC	−0.054 (−0.103; −0.006)	.027	−0.048 (−0.099; 0.003)	.066
Insulin sensitivity
HOMA	0.010 (−0.037; 0.057)	.690	0.016 (−0.033; 0.065)	.519
ISI	−0.008 (−0.053; 0.036)	.712	−0.012 (−0.058; 0.035)	.625
Insulin secretion
DI	−0.063 (−0.114; −0.012)	.016	−0.059 (−0.115; −0.003)	.038
CIR	−0.070 (−0.122; −0.108)	.008	−0.056 (−0.111; −0.002)	.042

p¹ – linear regression models are adjusted for sex, age, BMI. Change models were adjusted for sex, baseline BMI, body mass index change, age at baseline, change in age.

p² – linear regression models are adjusted for sex, age, BMI, smoking, alcohol use, physical activity at respective visit(s), and education at baseline. Change models are adjusted for sex, baseline age, BMI and education and change between baseline and follow-up in age and BMI and smoking, alcohol use and physical activity at both visits.

Figure 1. Change between follow-up and baseline visits in fasting insulin (panel A), HOMA-IR (panel B) according to the daylight and the MTRN1B rs10830963 genotype.