Laser Acupuncture for Adolescent Smokers—A Randomized Double-Blind Controlled Trial

American Journal of Chinese Medicine, Summer-Fall, 2000 by Cai Yiming, Zhao Changxin, Wong Song Ung, Zhang Lei, Lim Seuk Kean

Statistical Analysis

Power analysis

Based on the results of a previous study by Tan of adult smokers a response of 26% was expected in the control and approximately 80% in the experimental group (Tan, 1990). Allowing for a placebo effect of 25% and an effectiveness of at least 45% in the treatment group, a sample size of 165 in each group was required for this study.

Statistical analysis

Initial analysis will include the chi-square test (for categorical variables) to compare the two groups on demographic and other variables.

Results

Two hundred and sixty-eight (268) adolescent smokers finally completed the study, 200 males and 68 females. One hundred and twenty-eight received laser acupuncture treatment and one hundred and forty received sham acupuncture. Sixty-two subjects failed to complete a minimum of six treatment sessions, giving a dropout rate of almost 19%. There are 30 (48.4%) and 32 (51.6%) in the control and treatment groups respectively.

Subject characteristics showed that they had a history of smoking ranging from three months to 10 years and the number of cigarettes from 5 to 30 sticks per day. The majority was asked by school authorities to come for treatment.

Immediately after treatment, both groups showed a strong positive outcome with around 21% stopping smoking completely and around 80% reducing the average number of cigarettes smoked per day by at least half. The results are shown in Table 1.

Table 1. Effectiveness of Laser Treatment in Smoking Cessation

                           Immediately After Treatment

                                               Reduction
                                              [is greater
             No. of     Complete              than or equal     P-
Group       Patients   Cessation    P-Value     to] 50%       Value

Treatment     128      28 (21.9%)    0.95     105 (82.0%)     0.90
Control       140      30 (21.4%)             113 (80/7%)

                          Three Months After Treatment

                                               Reduction
                                              [is greater
             No. of     Complete              than or equal    P-
Group       Patients   Cessation    P-Value     to] 50%       Value

Treatment     101      25 (24.8%)    0.94      75 (74.3%)     0.95
Control       107      28 (26.2%)              78 (72.9%)

At follow-up three months later, the outcome of both groups was not significantly different (p [greater than] 0.05). The overall effectiveness of both groups was lowered to just over 24% (complete cessation) and 70% (reduction of cigarettes smoked per day by at least half) as shown in Table 1. Hence, there was no significant difference between the outcomes of the two groups.

Many factors, which may confound the outcome of the treatment and control groups, were measured and compared. These are shown in Tables 2 and 3.

Table 2. Comparing Characteristics of Two Groups

                            Related Factors

Group        No. of    Reactions to   P-Value     Family
            Patients    Treatment                 Members
                                                   Smoke

Treatment     128       26 (20.3%)      0.94    72 (56.3%)
Control       140       29 (20.7%)              83 (59.3%)

                            Related Factors

Group       P-Value      Close      P-Value     Asked to    P-Value
                        Friends                 Come for
                         Smoke                 Treatment

Treatment             123 (96.1%)    0.63     114 (89.1%)    0.42
Control      0.70     137 (97.8%)             119 (85.0%)