Energy drink usage by students attending an online university

Figures & data

Figure 1. Scheme for subject inclusion in data analysis.

Table 1. Subject characteristics.

				Frequent drinkers
	Infrequent drinkers (n = 116)	Frequent drinkers (n = 154)	p-value	< 10 drinks/month (n = 94)	>10 drinks/month (n = 60)	p-value
Age (years)	32 ± 7 ^a	31 ± 6	0.042	30 ± 6	32 ± 7	0.164
Number of drinks/month		12.1 + 18.5		3 ± 2	26 ± 24	<0.001
Total Physical Activity (MET-minutes/week)	12115 ± 15825	14039 ± 17841	0.416	14327 ± 20689	13252 ± 13264	0.663
	%	%	p-value	%	%	p-value
Gender
Female	39.7	26.0	0.017	34.0	13.3	0.0046
Male	60.3	74.0		66.0	86.7
Marital Status
Divorced	6.9	4.5	0.223	4.3	5.0	0.183
Engaged	4.3	0.6		1.1	10.0
In a relationship	9.5	6.5		4.3	75.0
Married	67.2	72.1		70.2	8.3
Single	12.1	15.6		20.2	1.7
Widowed	0.0	0.6
Employed
No	11.2	5.8	0.115	6.4	5.1	0.740
Yes	88.8	93.5		93.6	94.9
Employed by military
No	38.8	20.8	0.001	24.5	15.0	0.049
Yes	61.2	79.2		75.5	85.0
Hours worked
Less than 40 h	47.4	29.2	0.006	30.9	26.7	0.578
Over 40 h	52.6	70.8		69.1	73.3
Hours Spent Studying
1-5	24.1	19.5	0.834	20.2	18.3	0.801
6-10	37.1	44.2		41.5	48.3
11-15	19.8	22.1		22.3	21.7
16-20	12.1	9.7		11.7	6.7
21-25	2.6	1.9		2.1	1.7
25-30	1.7	0.6		1.1
Over 30 h	1.7	1.9		1.1	3.3

a Average ± SD; NS = not significant.

Table 2. Frequency subjects experienced specific adverse side effects associated with consuming energy drinks.

					95% Confidence interval
Variable ^a ^, ^b	B	Wald	p-value	Exp(B)	Lower	Upper
Infrequent (Ref value) vs. frequent
Headache	–0.460	2.070	0.150	0.631	0.338	1.181
Jitters	–0.286	1.133	0.287	0.752	0.444	1.271
Jolt	–0.042	0.021	0.884	0.959	0.546	1.682
Heart Palpation	–0.402	1.481	0.224	0.669	0.350	1.278
Speeding	–0.326	0.848	0.357	0.722	0.360	1.445
Shaking	–0.180	0.326	0.568	0.835	0.450	1.551
<10 drinks per month (Ref value) vs. >10 drinks per month
Headache	1.260	6.631	0.010	3.527	1.351	9.206
Jitters	0.220	0.346	0.556	1.247	0.598	2.597
Jolt	0.220	0.320	0.572	1.246	0.581	2.672
Heart Palpation	0.155	0.105	0.745	1.167	0.459	2.970
Speeding	1.360	6.525	0.011	3.896	1.372	11.062
Shaking	0.649	2.035	0.154	1.914	0.784	4.672

^aVariables accounted for in analysis were age, gender, hours worked, and military status.

^bReference for all statements is no.

Table 3. The number of subjects that used energy drinks for specific daily activities.

					95% Confidence interval
Variable ^a ^, ^b	B	Wald	p-value	Exp(B)	Lower	Upper
Infrequent (Ref value) vs. Frequent
School or Schoolwork	2.308	34.820	<0.001	10.050	4.670	21.629
Work	3.044	65.627	<0.001	20.979	10.046	43.809
Event or Competition	2.241	25.650	<0.001	9.4	3.949	22.372
Pick me up	2.698	56.689	<0.001	14.857	7.360	29.991
Lack of rest	2.827	43.478	<0.001	16.899	7.293	39.161
More energy	2.276	43.100	<0.001	9.742	4.937	19.223
Keep awake driving	2.750	34.030	<0.001	15.645	6.210	39.415
<10 drinks per month (Ref value) vs. >10 drinks per month
School or Schoolwork	1.489	11.640	0.001	4.433	1.884	10.427
Work	1.502	8.896	0.003	4.489	1.673	12.043
Event or Competition	0.956	4.563	0.033	2.601	1.082	6.250
Pick me up	0.123	0.086	0.769	1.131	0.496	2.579
Lack of rest	0.798	3.583	0.058	2.222	0.972	5.079
More energy	1.739	14.153	<0.001	5.692	2.300	14.085
Keep awake driving	0.066	0.027	0.868	1.068	0.488	2.338

a Variables accounted for in analysis were age, gender, hours worked, and military status.

b Reference for all statements is no.

Table 4. Quantity of energy drinks consumed for specific daily activities.

	mean + SD	F	p-value	Partial ETA squared	Observed power		mean + SD	F	p-value	Partial Eta Squared	Observed Power
On an average day when you haven’t gotten enough sleep, how many energy drinks do you drink per day?
Infrequent	0.2 + 0.6	43.05	<.0001	0.150	1.00	<10 drinks/month	0.6 + 0.8	24.02	<.0001	0.146	1.00
Frequent	0.9 + 0.9					>10 drinks/month	1.3 + 1.1
On average, how many times a month do you consume energy drinks because you did not get enough sleep?
Infrequent	0.3 + 0.9	29.46	<.0001	0.107	1.00	<10 drinks/month	2.1 + 3.7	22.79	<.0001	0.139	1.00
Frequent	4.5 + 7.5					>10 drinks/month	7.9 + 10.0
On the average day, when you are studying for an exam or a major project, how many energy drinks do you have?
Infrequent	0.1 + 0.4	13.82	<.0001	0.054	0.96	<10 drinks/month	0.2 + 0.5	23.49	<.0001	0.143	1.00
Frequent	0.5 + 0.8					>10 drinks/month	0.9 + 1.1
On average, how many times a month do you have energy drinks when you are studying for an exam or a major project?
Infrequent	0.2 + 0.67	7.59	0.006	0.030	0.78	<10 drinks/month	0.4 + 0.9	14.13	<.0001	0.091	0.96
Frequent	1.8 + 6.1					>10 drinks/month	3.9 + 9.3
On the average day, when you are driving for a long period, how many energy drinks do you have?
Infrequent	0.3 + 0.6	51.87	<.0001	0.175	1.00	<10 drinks/month	0.9 + 1.1	10.26	0.002	0.068	0.89
Frequent	1.3 + 1.2					>10 drinks/month	1.6 + 1.5
How many times do you drive and use energy drinks in an average month?
Infrequent	0.4 + 2.0	15.74	<.0001	0.061	0.98	<10 drinks/month	1.2 + 2.3	8.89	0.003	0.059	0.84
Frequent	2.2 + 4.3					>10 drinks/month	3.3 + 6.1
On an average night of partying, how many energy drinks do you mix with alcohol (example: Red Bull with vodka)?
Infrequent	0.2 + 0.6	11.32	0.001	0.045	0.92	<10 drinks/month	0.75 + 1.6	1.04	0.310	0.007	0.17
Frequent	0.8 + 1.8					>10 drinks/month	0.9 + 2.1
How many times do you party in an average month?
Infrequent	0.8 + 1.4	2.69	0.102	0.011	0.37	<10 drinks/month	1.2 + 1.6	1.70	0.195	0.012	0.25
Frequent	1.7 + 4.8					>10 drinks/month	2.5 + 7.4
On an average day, when you have a hangover, how many energy drinks do you have?
Infrequent	0.1 + 0.3	2.48	0.117	0.010	0.35	<10 drinks/month	0.03 + 0.5	2.82	0.095	0.020	0.39
Frequent	0.2 + 0.9					>10 drinks/month	0.3 + 1.3
How many times do you use energy drinks to recover from a hangover in an average month?
Infrequent	0.02 + 0.1	1.47	0.227	0.006	0.23	<10 drinks/month	0.02 + 0.6	2.11	0.149	0.015	0.30
Frequent	0.5 + 3.5					>10 drinks/month	0.9 + 5.4

Table 5. Respondents’ agreement/disagreement with the following statements.

	B	Wald	p-value	Exp(B)	95% Confidence interval for EXP(B)
Variable^a^,^b					Lower	Upper
Infrequent (Ref. value) vs. Frequent
I am completely aware of what taurine is.	–0.169	1.091	0.296	0.844	0.614	1.160
I am completely aware of what guarana is.	–0.103	0.405	0.524	0.902	0.657	1.239
I know what B-vitamins are.	–0.314	1.181	0.277	0.731	0.415	1.287
The average college student consumes too much caffeine.	0.253	0.957	0.328	1.288	0.776	2.138
I consume too much caffeine.	–0.246	2.426	0.119	0.782	0.574	1.066
I am aware of all the enhancing ingredients in energy drinks	0.275	2.655	0.103	1.316	0.946	1.833
Energy drinks are safer than energy-enhancing pills such as Stackers, Mini-Thins, Yellow-Jackets, etc.	–0.531	7.571	0.006	0.588	0.403	0.858
Energy drinks are more effective than coffee.	–0.573	9.603	0.002	0.564	0.393	0.810
Drinking energy drinks are the same as drinking coffee.	–0.020	0.010	0.921	0.980	0.657	1.462
Drinking energy drinks is more effective than drinking soft drinks.	–0.763	17.054	<0.001	0.466	0.325	0.670
Drinking energy drinks are the same as drinking soft drinks.	0.067	0.095	0.758	1.069	0.698	1.639
<10 drinks/month (Ref. value) vs. >10 drinks/month
I am completely aware of what taurine is.	–0.471	3.695	0.055	0.624	0.386	1.009
I am completely aware of what guarana is.	–0.680	7.435	0.006*	0.507	0.311	0.826
I know what B-vitamins are.	–0.894	3.209	0.073	0.409	0.154	1.088
The average college student consumes too much caffeine.	0.376	1.432	0.231	1.456	0.787	2.694
I consume too much caffeine.	–0.944	16.641	<0.001	0.389	0.247	0.612
I am aware of all the enhancing ingredients in energy drinks	–0.717	8.744	0.003	0.488	0.303	0.785
Energy drinks are safer than energy-enhancing pills such as Stackers, Mini-Thins, Yellow-Jackets, etc.	–0.291	1.39	0.238	0.747	0.461	1.213
Energy drinks are more effective than coffee.	–0.856	11.411	0.001	0.425	0.259	0.698
Drinking energy drinks are the same as drinking coffee.	–0.583	4.869	0.027	0.558	0.333	0.937
Drinking energy drinks is more effective than drinking soft drinks.	–0.828	8.144	0.004	0.437	0.247	0.771
Drinking energy drinks are the same as drinking soft drinks.	0.304	1.229	0.268	1.355	0.792	2.320

a Variables accounted for in analysis were age, gender, hours worked, and military status.

^bReference for all statements is disagree.

* Beta error is equal to 0.67, so one should not over interpret the data to avoid a type 2 error. All other significant variables have a beta error >0.75.