This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2021R1G1A1011662).
No potential conflict of interest relevant to this article was reported.
With the development of treatment technology, the percentage of cancer survivors has continued to increase. However, the cognitive decline these patients experience has been overlooked because it is not related to survival. This study investigated factors related to memory problems in patients with cancer.
Using data from the 2019 Korea National Health and Nutrition Examination Survey (KNHANES), this secondary data analysis study attempted to identify factors related to memory problems in cancer survivors. Of the 8,110 survey participants, there were 6,296 adults, aged 19 years or older. Of these, 357 were diagnosed with cancer. Four participants were excluded due to missing values for occupation, income, and body mass index (BMI). Finally, 353 subjects were included in the research analysis. The data were statistically analyzed using IBM SPSS version 28.0.
218 (61.8%) of the cancer survivors reported memory problems. Having a lower-than-average individual income (odds ratio, OR=2.16, 95% confidence interval, CI=1.31-3.53,
Our findings suggest that it is necessary to develop cognitive rehabilitation programs for cancer survivors.
최근 치료기술의 발달로 암 생존자의 비율은 지속적으로 증가하고 있음에도 불구하고, 암 생존자가 경험하는 인지기능저하는 생존과 관련이 없어 상대적으로 간과되어 왔다. 따라서 본 연구에서는 암 생존자의 기억력 문제와 관련된 요인을 조사하기 위하여 시도되었다.
본 연구는 2019년 국민건강영양조사 자료를 이용한 2차자료 분석연구이다. 조사 대상자 8,110명 중 19세 이상 성인은 6,296명이었고, 이 중 357명이 암 진단 경험이 있었다. 4명의 참가자는 직업, 소득 및 체질량 지수의 결측값이 있어 제외한 후, 353명의 자료를 SPSS 28.0 프로그램을 사용하여 통계적으로 분석하였다.
암 생존자 중 218명(61.8%)이 기억력 문제를 보고하였다. 중앙값 이하의 개인소득(odds ratio, OR=2.16, 95% confidence interval, CI=1.31-3.53,
본 연구결과를 토대로 암 생존자의 기억력 문제와 관련된 요인을 교정할 수 있는 인지 재활 프로그램 개발이 필요하다.
Although the number of cancer patients in Korea has increased from 218,000 (2015) to 255,000 (2019) [
The term, cancer survivor, was first used by a pediatrician, Fitzhugh Mullan, in 1975 and has various definitions, depending on the literature [
Cancer-related cognitive impairment refers mainly to memory lapses or difficulty concentrating [
The tumor, sociodemographic or genetic factors, treatment, physiological problems, and lifestyle can all affect cognitive changes in cancer survivors [
This is a cross-sectional study using secondary data analysis. Using data from the 2019 KNHANES (a government-designated statistical database under the National Health Promotion Act), the study attempted to identify factors related to memory problems in cancer survivors.
The study sample included 353 adult cancer survivors who were enrolled in the 2019 KNHANES. Of the 8,110 participants in this study, there were 6,296 adults, aged 19 years or older. Of these, 357 were diagnosed with cancer including stomach, liver, colorectal, breast, cervical, lung, thyroid, and other cancers. Four patients were excluded due to missing values for occupation, income, and body mass index (BMI). A total of 353 individuals were included in the final analysis.
Measurements included general characteristics and factors related to health, such as health behaviors, psychological health, and physical health.
The study considered the following general characteristics: gender, age, education level, marital status, job, living alone status, and income. Gender was classified as male and female. Age was divided into young adults under the age of 40 years, middle age over 40 years old, older adults under 65 years of age, and elderly adults older than 65 years of age. Education level was divided into over high school and below middle school level. Marital status, job status, and living status were classified according to presence or absence. Income was divided into individuals’ quartile incomes above and below the median.
Health behaviors including drinking, smoking, sleep duration, activity restriction, walking, and strength exercises were considered. Drinking was classified according to whether drinking occurred during the past year and smoking was classified as smoking or non-smoking. Sleep duration was classified as an average daily sleep time of less than 6 hours, 7 to 8 hours, and 9 hours or more. Activity restrictions were classified according to current activity status. For physical activities, walking and strength exercises were classified as the number of days per week (5-7 days, 3-4 days, 1-2 days, and no exercise).
Psychological health was considered in terms of depression, stress, and patient-perceived health status. Depression was classified as present or absent, depending on whether the person had experienced depression for at least two consecutive weeks in the past year. Stress was categorized into rarely, somewhat, much, and a great deal, depending on the level of stress experienced in daily life. Perceived health status was reclassified as bad (including very bad and bad, neutral (or average), and good (including good and very good), depending on the patient's self-perception of their health.
Physical health factors considered in this study included BMI, hypertension, diabetes mellitus, and dyslipidemia. BMI (kg/m2) was considered, and participants were classified as obese (BMI was more than 25), overweight (BMI between 23-25), normal (BMI between 18.5 and 23), and underweight (BMI less than 18.5). Hypertension, diabetes, and dyslipidemia were classified according to presence or absence.
The dependent variable, memory problems, was defined as the participant's memory status during the past week. Participants who responded that they had no memory difficulty at all was classified as having “ no memory problems”. In contrast, participants who expressed occasional memory difficulties were classified as having “ some memory problems”, while those who responded that they experienced frequent trouble remembering things were classified as having “ extreme memory problems”.
The sampling frame included data from the 2016 population and housing census, while the stratification variables were obtained from the administrative division and housing type. Facilities, such as nursing homes, the military, prisons, and foreign households, were excluded from the sample survey frame. From the rolling sampling over 12 months, 8,110 individuals from 3,670 households participated in the survey.
The complex survey data were analyzed using SPSS 28.0 (IBM Corp., Armonk, NY, USA), according to the KNHANES guidelines of the Korea Disease Control and Prevention Agency (KCDC). Statistically,
The investigation in the first year (2019) of the 8th period was conducted after the approval of the IRB due to the collection of human materials and the disclosure of raw data (2018-01-03-C-A). This study was conducted with the approval of the IRB of University of Ulsan (IRB No.: 2022R0020).
The participants of this study included 353 cancer survivors. Of these, 135 (38.2%) participants indicated that they had no memory problems, 191 (54.1%) responded that they experienced memory problems sometimes, 25 (7.1%) had memory problems often, and 2 (0.6%) experienced constant memory problems. Most participants had a diagnosis of other cancers (93, 25.2%). In contrast, few participants were diagnosed with liver cancer (5, 1.4%) (
Characteristics of the cancer survivors (n=353, weighted n=1,934,029)
Characteristics | Categories | n (%) | Weighted n (%) | SE | 95% CI | |
---|---|---|---|---|---|---|
Lower | Upper | |||||
Memory problems | Never | 135 (38.2) | 789,122 (40.8) | 80,101 | 930,618 | 947,627 |
Sometimes | 191 (54.1) | 1,040,381 (53.8) | 79,027 | 884,001 | 1,196,760 | |
Often | 25 (7.1) | 95,267 (4.9) | 21,759 | 52,210 | 138,324 | |
Always | 2 (0.6) | 9,259 (0.5) | 7,052 | -4,696 | 23,213 | |
Cancer type |
Stomach | 54 (14.6) | 265,335 (13.7) | 41,471 | 183,271 | 347,340 |
Liver | 5 (1.4) | 41,084 (2.1) | 19,642 | 2,216 | 79,952 | |
Colorectal | 44 (11.9) | 233,859 (12.1) | 39,897 | 154,910 | 312,808 | |
Breast | 59 (16.0) | 340,389 (17.6) | 52,039 | 237,414 | 443,364 | |
Cervical | 21 (5.7) | 112,715 (5.8) | 27,922 | 57,463 | 167,968 | |
Lung | 18 (4.9) | 85,308 (4.4) | 23,549 | 38,708 | 131,908 | |
Thyroid | 75 (20.3) | 477,826 (24.7) | 63,487 | 352,198 | 603,455 | |
Other | 93 (25.2) | 484,621 (25.1) | 64,571 | 356,846 | 612,396 |
SE, standard error; CI, confidence interval.
Possible duplicate answers.
Of the demographic characteristics considered, job (
Demographic characteristics of the cancer survivors (n
Characteristics | Categories | Total | Memory problems | χ |
||||||
---|---|---|---|---|---|---|---|---|---|---|
No |
Sombre |
Extreme |
||||||||
n (%) | n (%) | Weighted |
n (%) | Weighted |
n (%) | Weighted |
||||
Gender | Men | 144 (40.8) | 58 (40.3) | 322,197 (16.7) | 73 (50.7) | 378,087 (19.5) | 13 (9.0) | 57,247 (3.0) | 2.75 | 0.241 |
Women | 209 (59.2) | 77 (36.8) | 466,926 (24.1) | 118 (56.5) | 662,294 (34.2) | 14 (6.7) | 47,278 (2.4) | |||
Age (y) | 19-39 | 16 (4.5) | 10 (62.5) | 64,216 (3.3) | 6 (37.5) | 49,012 (21.3) | 0 (0.0) | 0 (0.0) | 7.28 | 0.279 |
40-65 | 168 (47.6) | 64 (38.1) | 431,073 (22.3) | 98 (58.3) | 579,623 (19.5) | 6 (3.6) | 37,131 (1.9) | |||
≥65 | 169 (47.9) | 61 (36.1) | 293,834 (15.2) | 87 (51.5) | 411,746 (34.2) | 21 (12.4) | 67,394 (3.5) | |||
Education level | ≤Middle school | 147 (41.6) | 50 (34.0) | 252,614 (13.1) | 79 (53.7) | 375,665 (30.0) | 18 (12.3) | 57,063 (3.0) | 3.84 | 0.196 |
≥High school | 206 (58.4) | 85 (41.2) | 536,508 (27.7) | 112 (54.4) | 664,716 (34.4) | 9 (4.4) | 47,462 (2.5) | |||
Marital status | With spouse | 273 (77.3) | 106 (38.8) | 609,055 (31.5) | 146 (53.5) | 814,557 (42.1) | 21 (7.7) | 83,574 (4.3) | 0.11 | 0.948 |
Without spouse | 80 (22.7) | 29 (36.3) | 180,068 (9.3) | 45 (56.2) | 225,824 (11.7) | 6 (7.5) | 20,951 (1.1) | |||
Job | Yes | 146 (41.4) | 67 (45.9) | 397,337 (20.5) | 75 (51.4) | 418,696 (21.6) | 4 (2.7) | 13,848 (0.7) | 10.66 | 0.008 |
No | 207 (58.6) | 68 (32.9) | 391,785 (20.3) | 116 (56.0) | 621,684 (32.1) | 23 (11.1) | 90,677 (4.7) | |||
Living alone status | Yes | 313 (88.7) | 124 (39.6) | 742,053 (38.4) | 165 (52.7) | 947,815 (49.0) | 24 (7.7) | 91,178 (4.7) | 1.62 | 0.461 |
No | 40 (11.3) | 11 (27.5) | 47,070 (2.4) | 26 (65.0) | 92,566 (4.8) | 3 (7.5) | 13,347 (0.7) | |||
Income | Lower-than-median | 165 (46.7) | 49 (29.7) | 285,877 (14.8) | 101 (61.2) | 563,551 (29.1) | 15 (9.1) | 57,572 (3.0) | 11.13 | 0.008 |
Higher-than-median | 188 (53.3) | 86 (45.7) | 503,245 (26.0) | 90 (47.9) | 476,830 (24.7) | 12 (6.4) | 46,953 (2.4) |
Unweighted sample size.
Weighted sample size.
Of the health characteristics examined, drinking (
Characteristics related to health of the cancer survivors (n
Characteristics | Categories | Total | Memory loss | χ |
||||||
---|---|---|---|---|---|---|---|---|---|---|
No |
Some |
Extreme |
||||||||
n (%) | n (%) | Weighted |
n (%) | Weighted |
n (%) | Weighted |
||||
Health behaviors | ||||||||||
Drinking | Yes | 175 (49.6) | 67 (38.3) | 403,000 (41.2) | 103 (58.9) | 553,835 (56.6) | 5 (2.8) | 22,307 (2.3) | 7.07 | 0.033 |
No | 178 (50.4) | 68 (38.2) | 386,123 (40.4) | 88 (49.4) | 486,546 (51.0) | 22 (12.4) | 82,218 (8.6) | |||
Smoking | Yes | 139 (39.4) | 48 (34.5) | 268,032 (13.9) | 76 (54.7) | 383,809 (19.8) | 15 (10.8) | 67,976 (3.5) | 6.98 | 0.040 |
No | 214 (60.6) | 87 (40.7) | 521,090 (26.9) | 115 (53.7) | 656,572 (33.9) | 12 (5.6) | 36,549 (1.9) | |||
Sleep duration (hours) | Deprived sleep (≤6) | 156 (44.3) | 52 (33.3) | 275,012 (33.0) | 94 (60.3) | 515,091 (61.8) | 10 (6.4) | 43,476 (5.2) | 9.94 | 0.070 |
7-8 | 170 (48.3) | 72 (42.4) | 468,627 (47.8) | 86 (50.6) | 466,210 (47.6) | 12 (7.1) | 43,850 (4.5) | |||
≥9 | 26 (7.4) | 11 (42.3) | 45,483 (38.1) | 11 (42.3) | 59,080 (49.5) | 4 (15.4) | 14,806 (12.4) | |||
Activity restriction | Yes | 52 (14.7) | 17 (32.7) | 102,989 (5.3) | 24 (46.2) | 107,609 (5.6) | 11 (21.1) | 34,924 (1.8) | 8.35 | 0.055 |
No | 301 (85.3) | 118 (39.2) | 686,134 (35.5) | 167 (55.5) | 932,772 (48.2) | 16 (5.3) | 69,601 (3.6) | |||
Walking (days per 1 week) | 5-7 | 170 (48.2) | 76 (44.7) | 450,466 (23.3) | 84 (49.4) | 460,795 (23.8) | 10 (5.9) | 41,194 (2.1) | 18.59 | 0.023 |
3-4 | 82 (23.2) | 24 (29.3) | 149,126 (7.7) | 55 (67.1) | 319,622 (16.5) | 3 (3.6) | 8,829 (0.5) | |||
1-2 | 43 (12.2) | 14 (32.6) | 72,520 (3.7) | 25 (58.1) | 127,520 (6.6) | 4 (9.3) | 13,895 (0.7) | |||
Never | 58 (16.4) | 21 (36.2) | 117,011 (6.1) | 27 (46.6) | 132,444 (6.8) | 10 (17.2) | 40,607 (2.1) | |||
Strength exercises (days per 1 week) | 5-7 | 30 (8.5) | 15 (50.0) | 92,563 (4.8) | 13 (43.3) | 60,153 (3.1) | 2 (6.7) | 4,414 (0.2) | 8.58 | 0.237 |
3-4 | 29 (8.2) | 8 (27.6) | 48,096 (2.5) | 20 (69.0) | 101,695 (5.3) | 1 (3.4) | 7,496 (0.4) | |||
1-2 | 24 (6.8) | 7 (29.2) | 41,396 (2.1) | 16 (66.7) | 97,507 (5.0) | 1 (4.1) | 1,372 (0.1) | |||
Never | 270 (76.5) | 105 (38.9) | 607,068 (31.4) | 142 (52.6) | 781,027 (40.4) | 23 (8.5) | 91,244 (4.7) | |||
Psychosocial health | ||||||||||
Depression | Yes | 47 (13.3) | 9 (19.1) | 47,341 (2.4) | 28 (59.6) | 142,150 (7.3) | 10 (21.3) | 39,495 (2.0) | 17.62 | 0.002 |
No | 306 (86.7) | 126 (41.2) | 741,781 (38.4) | 163 (53.3) | 898,231 (46.4) | 17 (5.5) | 65,030 (3.4) | |||
Stress | Rarely | 71 (20.1) | 43 (60.6) | 246,010 (12.7) | 25 (35.2) | 115,757 (6.0) | 3 (4.2) | 14,002 (0.7) | 23.50 | <0.001 |
Somewhat | 209 (59.2) | 70 (33.5) | 413,691 (21.4) | 123 (58.9) | 666,906 (34.5) | 16 (7.6) | 63,751 (3.3) | |||
Much | 60 (17.0) | 18 (30.0) | 108,770 (5.6) | 37 (61.7) | 233,278 (12.1) | 5 (8.3) | 20,100 (1.0) | |||
A great deal | 13 (3.7) | 4 (30.8) | 20,650 (1.1) | 6 (46.1) | 24,440 (1.3) | 3 (23.1) | 6,672 (0.3) | |||
Perceived health status | Bad | 99 (28.0) | 34 (34.3) | 191,348 (9.9) | 51 (51.6) | 248,297 (12.8) | 14 (14.1) | 59,032 (3.1) | 10.00 | 0.042 |
Neutral | 180 (51.0) | 67 (37.2) | 427,923 (22.1) | 104 (57.8) | 575,902 (29.8) | 9 (5.0) | 34,329 (1.8) | |||
Good | 74 (21.0) | 34 (45.9) | 169,851 (8.8) | 36 (48.7) | 216,182 (11.2) | 4 (5.4) | 11,164 (0.6) | |||
Physical health | ||||||||||
Body mass index | Obesity | 109 (30.9) | 30 (27.5) | 26,173 (1.4) | 69 (63.3) | 15,404 (0.8) | 10 (9.2) | 9,874 (0.5) | 4.65 | 0.096 |
Overweight | 82 (23.2) | 34 (41.5) | 193,980 (10.0) | 45 (54.9) | 36,607 (11.8) | 3 (3.6) | 6,570 (0.5) | |||
Underweight | 21 (5.9) | 9 (42.9) | 762,950 (39.4) | 8 (38.1) 1 | 1,024,977 (53.0) | 4 (19.0) | 94,651 (4.9) | |||
Normal | 141 (39.9) | 62 (44.0) | 333,178 (17.2) | 69 (48.9) | 433,115 (22.4) | 10 (7.1) | 40,121 (2.1) | |||
Hypertension | Yes | 130 (36.8) | 46 (35.4) | 265,530 (13.7) | 74 (56.9) | 381,131 (19.7) | 10 (7.7) | 34,808 (1.8) | 0.35 | 0.830 |
No | 223 (63.2) | 89 (39.9) | 523,593 (27.1) | 117 (52.5) | 659,250 (34.1) | 17 (7.6) | 69,717 (3.6) | |||
Diabetes mellitus | Yes | 49 (13.9) | 12 (24.5) | 75,490 (3.9) | 28 (57.1) | 142,702 (7.4) | 9 (18.4) | 31,761 (1.6) | 6.72 | 0.065 |
No | 304 (86.1) | 123 (40.5) | 713,632 (36.9) | 163 (53.6) | 897,679 (46.4) | 18 (5.9) | 72,765 (3.8) | |||
Dyslipidemia | Yes | 101 (28.6) | 38 (37.6) | 229,070 (11.8) | 53 (52.5) | 260,371 (13.5) | 10 (9.9) | 36,467 (1.9) | 1.27 | 0.593 |
No | 252 (71.4) | 97 (38.5) | 560,052 (29.0) | 138 (54.8) | 780,009 (40.3) | 17 (6.7) | 68,058 (3.5) |
Unweighted sample size.
Weighted sample size.
The “ some memory problems” had a great risk by 2.16 times in participants with a lower-than-median income compared to those with higher-than-median incomes (OR=2.16, 95% CI=1.31-3.53,
Multivariable multinomial logistic regression analysis of influencing factors to memory problems of the cancer survivors (n
Characteristics | Categories | Memory problems | |||||
---|---|---|---|---|---|---|---|
Some (reference, no) |
Extreme (reference, no) |
||||||
Adjusted OR | 95% CI | Adjusted OR | 95% CI | ||||
Job | Yes | 0.59 | 0.34-1.04 | 0.066 | 0.18 | 0.05-0.67 | 0.011 |
No | 1.00 | 1.00 | |||||
Income (individual) | Lower-than-median | 2.16 | 1.31-3.53 | 0.003 |
1.68 | 0.56-5.08 | 0.353 |
Higher-than-median | 1.00 | 1.00 | |||||
Drinking | Yes | 1.18 | 0.69-2.01 | 0.545 | 0.26 | 0.09-0.81 | 0.021 |
No | 1.00 | 1.00 | |||||
Smoking | Yes | 1.20 | 0.73-1.96 | 0.465 | 3.19 | 1.16-8.72 | 0.024 |
No | 1.00 | 1.00 | |||||
Walking (days per 1 week) | 5-7 | 0.84 | 0.36-1.96 | 0.680 | 0.30 | 0.07-1.33 | 0.112 |
3-4 | 1.50 | 0.56-4.05 | 0.420 | 0.15 | 0.03-0.81 | 0.027 |
|
1-2 | 1.95 | 0.70-5.40 | 0.199 | 0.64 | 0.08-5.05 | 0.671 | |
Never | 1.00 | 1.00 | |||||
Depression | Yes | 1.95 | 0.68-5.59 | 0.212 | 6.06 | 1.33-27.57 | 0.020 |
No | 1.00 | 1.00 | |||||
Stress | Rarely | 0.40 | 0.81-1.93 | 0.249 | 0.09 | 0.01-1.30 | 0.077 |
Somewhat | 1.37 | 0.33-5.65 | 0.660 | 0.37 | 0.04-1.76 | 0.339 | |
Much | 2.00 | 0.45-8.96 | 0.364 | 0.48 | 0.16-10.96 | 0.513 | |
A great deal | 1.00 | 1.00 | |||||
Perceived health status | Bad | 0.59 | 0.27-1.32 | 0.199 | 0.88 | 0.33-1.43 | 0.879 |
Neutral | 0.69 | 0.33-1.43 | 0.310 | 0.47 | 0.13-1.76 | 0.262 | |
Good | 1.00 | 1.00 |
OR, odd ratio; CI, confidence interval.
Unweighted sample size.
Weighted sample size.
This study examined the factors associated with subjective memory problems in cancer survivors. In this study, 7.7% of the cancer survivors indicated frequent memory problems (often or always). Overall, 54.1% experienced memory problems. According to the American Society of Clinical Oncology [
Having a job decreased “ extreme memory problems” by 0.18 times, while having a lower-than-median individual income increased “ some memory problems” by 2.16 times. Of note, cognitive problems can affect productivity among working cancer survivors [
Interestingly, drinking alcohol significantly decreased “ extreme memory problems”. Previous study has reported significant associations between alcohol consumption and mild cognitive impairment [
Meanwhile, smoking increased the risk of “ extreme memory problems”. Smoking temporarily improved attention and memory, but decreased cognitive functions in middle-aged adults [
Walking three to four days a week significantly lowered the risk of memory problems by 0.15 times compared to not walking. In a meta-analysis, physical activities effectively increased cognitive functions in adults over 50 years of age [
Depression was a significant factor contributing to “ extreme memory problems”. In a previous study by Lee [
The importance of managing cognitive problems in cancer survivors may have been overlooked. There is limited relevant data on memory problems among the adverse side effects related to patients with cancers [
This study has some limitations. This study was a secondary data analysis. As such, it was not possible to consider whether chemotherapy was administered or when the cancer diagnosis was made. It is also possible that only relatively healthy cancer survivors eligible to participate in the national data collection were included. Furthermore, as memory problems were subjectively reported only, it was not possible to confirm an objective cognitive decline.
This study aimed to identify factors related to memory problems in cancer survivors by using data from the 2019 KNHANES. The results demonstrated that more than half of the cancer survivors reported memory problems. Having a lower-than-median individual income, smoking, and depression were significant potentiating factors, whereas having a job, drinking, and walking three to four days a week reduced the risk of memory problems. Based on the results of this study, it is necessary to develop interventions to improve the cognitive function of cancer survivors.