|
| |
 |
|
| ORIGINAL ARTICLE |
|
| Year : 2022 | Volume
: 71
| Issue : 3 | Page : 214-219 |
|
Relationship between digit ratio of 2D:4D and The physical health among college students of han ethnicity in Southern Fujian
Tongjun Chen1, Jianmei Xiang2, Shaokang Teng1, Zhongqing Huang1, Xiaoliang Li1, Liping Huang1, Huihua Chen1, Baoying Luo1
1 Department of Basic Medicine and Department of Clinical Medicine, Zhangzhou Health Vocational College; Fujian Collaborative Innovation Center for Translation Medical Testing and Application Technology, Zhangzhou, Fujian Province, China
2 Department of Rehabilitation Medicine, Zhangzhou Municipal Hospital of Fujian Province, Zhangzhou, Fujian Province, China
| Date of Submission | 19-Nov-2021 |
| Date of Decision | 29-Jan-2022 |
| Date of Acceptance | 21-Jun-2022 |
| Date of Web Publication | 20-Sep-2022 |
Correspondence Address:
Prof. Tongjun Chen
Zhangzhou Health Vocational College, Zhangzhou, Fujian Province; Fujian Collaborative Innovation Center for Translation Medical Testing and Application Technology, Zhangzhou, Fujian Province
China
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/jasi.jasi_189_21
Introduction: Studying the association between finger length ratios of 2D:4D and the physical health among college students of Han ethnicity in Southern Fujian can provide an indirect macrobiology reference index for early predictions of physical health status. Material and Methods: A total of 835 students in Southern Fujian were selected as test subjects through a stratified cluster sampling method. The 2D:4D ratio was recorded using physical measurement methods. The body mass index (BMI), vital capacity, 50-m run, and sit-and-reach test results were collected and analyzed based on the National Student's Health Standards. Results: Among male Han college students in Southern Fujian, the left 2D:4D ratio was negatively correlated with the vital capacity and sit-and-reach test results, while the right 2D:4D ratio was negatively correlated with the vital capacity, 50-m run, and sit-and-reach test results, as well as the comprehensive evaluation result of physical health. Among female Han college students in Southern Fujian, the left 2D:4D ratio was positively correlated with BMI and negatively correlated with the vital capacity, 50-m run, and 800-m run results, as well as the comprehensive evaluation result of physical health. The right 2D:4D ratio was negatively correlated with the vital capacity, 50-m run, 800-m run, and sit-and-reach test results, as well as the comprehensive evaluation results of physical health. The comprehensive evaluation results of physical health were statistically significant differences among low, medium, and high bilateral 2D:4D groups of female students, with poorer results in the high 2D:4D group than that of the medium and low 2D:4D groups. Discussion and Conclusion: The bilateral 2D:4D ratio of female and right 2D:4D ratio of male Han college students in Southern Fujian has a correlation with the comprehensive evaluation of physical health, which can serve as one of the reference indexes for adolescents' early health education, physical health monitoring, dietary intervention, and athlete selection.
Keywords: College students, digit ratio, Han ethnic group, Southern Fujian, the physical health
How to cite this article:
Chen T, Xiang J, Teng S, Huang Z, Li X, Huang L, Chen H, Luo B. Relationship between digit ratio of 2D:4D and The physical health among college students of han ethnicity in Southern Fujian. J Anat Soc India 2022;71:214-9 |
How to cite this URL:
Chen T, Xiang J, Teng S, Huang Z, Li X, Huang L, Chen H, Luo B. Relationship between digit ratio of 2D:4D and The physical health among college students of han ethnicity in Southern Fujian. J Anat Soc India [serial online] 2022 [cited 2023 Mar 28];71:214-9. Available from: https://www.jasi.org.in/text.asp?2022/71/3/214/356492 |
| Introduction | |  |
The Student's Physique and Health Standard was introduced in 2002 in China. After further exploration and a summary of experience, the National Student Physical Health Standard (Revised in 2014) (hereinafter referred to as “The Standard”) was issued by the Ministry of Education, to assess students' physical health from their body shape, function, and fitness. This lays a good foundation for providing reference standards on the development of students' physical health.
Digit ratio refers to the ratio of finger lengths. The length of the thumb to the little finger (1–5) is expressed as 1D-5D; however, it is generally difficult to determine the length of the thumb, so 2D:3D, 2D:4D, 2D:5D, 3D:4D, 3D:5D and 4D:5D are usually used, of which the second finger–to fourth finger length ratio (2D:4D) is most commonly used. Digit ratio is determined by the HOX gene[1] and is affected by intrauterine sex hormones during embryonic development,[2] with a positive correlation with maternal intrauterine testosterone and a negative correlation with estrogen. Human right-hand 2D:4D is negatively correlated with the testosterone/estradiol ratio in amniotic fluid.[3] Digit ratio remains unchanged during individual growth, so it can serve as a marker for perinatal sex hormone levels. In addition to digit ratio, body mass index (BMI), exercise skills, and exercise capacity are also associated with perinatal sex hormone levels.[4],[5],[6] Scholars found that prenatal sex hormone levels have a certain impact on the flexibility and muscle strength of adolescent females.[7] A lower 2D:4D often corresponds to a better physical ability and greater exercise performance.[8] especially in athletes involving in aerobic exercise[5] including rowing athletes,[9] elite tennis players,[10] and swimmers.[11] Perinatal sex hormone levels are also related to body size and the distribution of substances in the body.[12] Digit ratio (2D:4D) is associated with individual development and physical function[13],[14] but the relationship differs among ethnic groups in different regions.[15] Therefore, the relationship between digit ratio and physical health, assessed by BMI, cardiopulmonary function, and exercise capacity, deserves further attention and research. In the present study, the correlation between 2D:4D and physical health, and the possibility of an indirect macrobiological index for early prediction of physical health were explored among Han college students in Southern Fujian Province of China.
| Material and Methods | | |
Material
Eight hundred and thirty-five participants (303 males and 532 females) aged 17–21-year-old were selected from undergraduate classes of 2018 and 2019 attending Zhangzhou Health Vocational College in Fujian Province. The participants were chosen through stratified random cluster sampling from September 2018 to January 2020. The inclusion criteria include: Han people in Southern Fujian (Zhangzhou, Xiamen and Quanzhou) within 3 generations; no major somatopsychic illness; no dyskinesia, no injured or deformed fingers, having never received special physical training, and with a mother that did not take any hormone drugs during pregnancy. This study was reviewed and approved by the Ethics Department of the college, and informed consent was obtained from all students.
Methods
According to the Anthropometric Manual authored by Shao XQ,[16] the finger length of subjects was measured through the indirect method, specifically as follows: The photos of both palms were taken using a digital camera at a fixed shooting distance. Then, the measuring point of each finger was marked using the image analysis software on a computer, and the photos were printed in color [Figure 1]. Finally, the straight-line distance between the midpoint of the palmar flexural fold of the proximal phalanx and the midpoint of the fingertip was measured using an electronic digimatic caliper (Guanglu Measuring Instrument Co., Ltd., China, 0–150 mm, precision: 0.01 mm).
A total of eight indexes were measured for each subject according to the requirements and regulations in The Standard,[17] including body shape indexes (height [cm] and weight [kg]), body function indexes (vital capacity [mL]), and body fitness indexes (speed fitness test: 50-m run [s], flexibility fitness test: Sit-and-reach (cm), lower limb explosive strength test: Standing broad jump [cm], strength fitness test: Chin-up for males [times] and 1 min crunches for females [times], endurance fitness test: 1000-m run for males [s] and 800-m run for females [s]). The vital capacity was measured in a standing position using a spirometer. Each subject repeated the test twice with an interval of 30 s. The sit-and-reach test was measured using a sit and reach box (brand, city). The subject sat with legs stretched and feet 10–15 cm apart on the test board. They were instructed to bend forward and push the cursor as far as they could. The test was repeated twice. The higher of the two was used in the analysis. The standing broad jump test measures the distance of the double leg jump in centimeters. The 1 min crunches test measures how many crunches the subject can do in a minute. The testing position was supine with foot on the plinth, hips and knees at 90°, and fingers crossed behind the head. A tester held the subject's ankle for fixation. A successful attempt is counted when the subject completing the sitting-up with the elbow touching the knees while keeping the hands behind or around the head. The 50-m run test and 1000-m (800-m) run test were measured in seconds using a stopwatch. Height and weight were measured and BMI was calculated as weight (kg)/height (m)2. The test results were assessed according to The Standard.
Quality control
Two testers received standardized training before the start of the study. Intrarater and interrater reliabilities were assessed using correlation coefficient and reached 0.94 or higher in all tests using in this study.
Statistical procedures
A database was set up using EpiData 3.1 (EpiData Association; Odense, Denmark) software. SPSS 22.0 (IBM Corp. Armonk, NY, USA) software was utilized for all statistical analyses. Descriptive analysis was expressed as mean ± standard deviation (χ ± s). Reliability and correlation were analyzed using Pearson correlation analysis and variance tests. ANOVA and post hoc analyses were used to compare the differences among the three groups. The significance level was set at α = 0.05.
| Results | | |
Among Han male college students in Southern Fujian, the left 2D:4D was negatively correlated with vital capacity and sit-and-reach results, but had no correlations with other indexes. The right 2D:4D was negatively correlated with vital capacity, 50-m run, sit-and-reach results, and the total score of physical health, but had no correlations with other indexes [Table 1]. | Table 1: The correlation analysis between finger length ratio of second finger–to fourth finger length ratio and the physical health related indexes of College Students of Han male ethnic in southern Fujian (r)
Click here to view |
Among Han female college students in Southern Fujian, the left 2D:4D was positively correlated with BMI, and negatively correlated with vital capacity, 50-m run, 800-m run, and the total score of physical health. The right 2D:4D was negatively correlated with vital capacity, 50-m run, 800-m run, sit-and-reach results, and the total score of physical health [Table 2]. | Table 2: The correlation analysis between finger length ratio of second finger–to fourth finger length ratio and the physical health related indexes of College Students of Han female ethnic in southern Fujian (r)
Click here to view |
Using the 25th and 75th percentile of bilateral 2D:4D of Han college students in Southern Fujian as cutoff scores, all subjects were divided into low, mid, and high 2D:4D groups. It was found that the chin-up results had statistically significant differences among male right-hand low, mid, and high 2D:4D groups. The post hoc analysis revealed that the low 2D:4D group is significantly different from the mid and high 2D:4D groups [Table 3]. | Table 3: Differences in physical health-related indexes in bilateral low, medium and high second finger–to fourth finger length ratio groups among College Students of Han male ethnic in southern Fujian (X̄±S)
Click here to view |
The BMI, vital capacity, 50-m run and 800-m run results, and the total score were statistically significant differences among female left-hand low, mid, and high 2D:4D groups. The post hoc analysis revealed that the high 2D:4D group is different from the mid and low 2D:4D groups. The 800-m run results had a statistically significant difference between mid and low 2D:4D groups. There were statistically significant differences in BMI, vital capacity, 50-m run, 800-m run, standing broad jump and sit-and-reach results, and the total score among female right-hand low, mid, and high 2D:4D groups. The vital capacity, 50-m run and sit-and-reach results and the total score all had statistically significant differences in the high 2D:4D group compared with those in the mid and low 2D:4D groups. Moreover, there was a statistically significant difference in BMI between high and low 2D:4D groups, and also in standing board jump results between high and mid 2D:4D groups [Table 4]. | Table 4: Differences in physical health-related indexes in bilateral low, medium and high second finger–to fourth finger length ratio groups among College Students of Han female ethnic in southern Fujian (X̄±S)
Click here to view |
| Discussion | | |
In October 2016, the 2030 Planning Outline of Healthy China was issued by the Central Committee of the Communist Party of China and the State Council of the PRC.[18] As stipulated in Section 4 of Chapter 6, adolescents are listed as the target population for the implementation of the physical health plan, and it is also required that the interest of adolescents in physical exercise be developed through the implementation of the youth sports promotion program, with an excellence rate of more than 25% in The Standard as a quantifiable goal. China has decided to enhance the physical health of students as an approach to achieve the goal of healthy China. The Standard comprehensively assesses the students' physical health from body shape, function, and fitness. Body shape indexes are an important basis reflecting the growth and development speed and nutritional status of the human body.[19] BMI displays the relation between adults' weight and height, which is recommended by the WHO as a preferred index for assessing overweight and obesity and their change trends and can also be used to measure the fat distribution in the human body.[20]
In the present study, the BMI was significantly higher among female students in the left-hand high 2D:4D group than that of the mid and low 2D:4D groups, and it was also significantly higher in the right-hand high 2D:4D group than that of the low 2D:4D group. Fink et al.[21] found that BMI positively correlates with left hand 2D:4D in males. In females, the reversed relationship was found but it was not statistically significant. Muller et al.[22] found that 2D:4D is not strongly associated with adult anthropometric measures. BMI is greatly affected by gender, ethnicity, living habits, age, and regional dietary rules. Therefore, the correlation results between 2D:4D and BMI in different regions, ethnicities, and genders are not consistent. It is well known that BMI reflects the overall body fat content, whereas the waist circumference and waist-to-hip ratio reflect the abdominal fat content. All three can reflect body fat content, but each has certain limitations. If an index, such as the 2D:4D can be used to represent all three measures then it can provide a useful alternative for estimating body composition.
Body function refers to the functional capability of organs and systems in the body. Vital capacity, i.e., maximum lung capacity in one-time ventilation, is an important index for assessing respiratory function. In this study, both male and female bilateral 2D:4D had a negative correlation with vital capacity, and vital capacity in the female bilateral high 2D:4D group was significantly lower than that of the mid and low 2D:4D groups. However, vital capacity was measured in a one-time ventilation test and closely related to height and weight, thus failing to fully reflect the elastic state of lung tissues and the patency degree of the airway,[23] so it had certain limitations. Therefore, vital capacity/weight ratio will be considered for future analysis, to display the differences in body function and physical activity more objectively and analyze their correlations with digit ratio (2D:4D) more scientifically and reasonably.
Body fitness is a general term for the speed, strength, endurance, and flexibility of the human body in muscle activities. Scholars in China also found the correlation between 2D:4D and human body fitness in research on the digit ratio of university students in Jinzhou and Guangdong youthsm,[24],[25] but the results are not consistent. In the present study, it was found that male bilateral 2D:4D was negatively correlated with the sit-and-reach results among Han college students in southern Fujian, indicating that males with lower right 2D:4D had better performance in the 50-m run. This result is consistent with the result from Manning and Hill on 241 boys.[5] Right 2D:4D had no correlation with the chin-up results, but the low 2D:4D group performed worse than those in the mid and high 2D:4D groups. Besides, this study found that females with higher right 2D:4D have poorer body flexibility. In addition, females with a lower bilateral 2D:4D finger length ratio had better endurance and speed. The result is consistent with those of Pasanen et al.[26] He studied the correlation between 2D:4D and sports performance of 114 boys and 175 girls and found that their sports performance was negatively correlated with the female bilateral 2D:4D and male right 2D:4D. However, the result differs from the result from Lombardo et al.[27] in which digit ratio and physical skills and fitness were negatively correlated on the right side of male, but not in female. We speculate that the difference may be due to the elite status of young athletes and the small sample size in the study by Lombardo et al. Whether the strength test results are associated with 2D:4D remains to be further analyzed after collecting more data from different types of strength tests in the future.
Through the comprehensive assessment of physical health based on The Standard, it was found that the higher female bilateral 2D:4D and male right 2D:4D indicated a lower total score of physical health, and the total score was significantly lower in the female high 2D:4D group than that of the mid and low 2D:4D groups. Experiments with rodents show that the length of 2D is positively influenced by prenatal exposure to estrogen, whereas the length of 4D is positively influenced by prenatal testosterone exposure.[28],[29],[30] In humans, 2D:4D is established by the end of the first trimester.[31] Prenatal testosterone exposure may also affect subsequent athletic behavior and performance.[32],[33],[34] Athletic prowess in both males and females, especially their performance on distance running,[35],[36],[37] is associated with smaller 2D:4D.[38],[39] The relationship between 2D:4D and athletic prowess may be mediated by the effects of prenatal testosterone exposure on the cardiovascular system.[39] Multiple lines of evidence suggest that prenatal testosterone exposure influences not only sports performance but also sports interest and motivation.[34],[40] It can be speculated that higher levels of androgen in individuals and mothers during embryonic development have a greater impact on the body function and fitness of females and males.
| Conclusion | | |
It was found that female bilateral 2D:4D and male right 2D:4D can serve as one of the macrobiological indexes indirectly predicting the physical health of college students, which offers a basis for early health education, physical health monitoring, lifestyle (diet) intervention, and athlete selection among adolescents. Body fitness is comprehensively assessed using a variety of parameters and affected by genetics, nutritional status and lifestyle. In this study, young Han college students in Southern Fujian were used as the subjects, thus reducing the errors caused by living environment, habits, human body development, and hormone levels in vivo to a certain extent. Other influencing factors, however, were not collected and analyzed, so further research is needed in future.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Luo TX, Huang CX. Research progress on human body deformity caused by HOX gene alteration. Foreign Med Sci (Section of Genetics) 2005;28:105-8.  |
| 2. | Manning JT, Callow M, Bundred PE. Finger and toe ratios in humans and mice: Implications for the aetiology of diseases influenced by HOX genes. Med Hypotheses 2003;60:340-3. |
| 3. | Lutchmaya S, Baron-Cohen S, Raggatt P, Knickmeyer R, Manning JT. 2 nd to 4 th digit ratios, fetal testosterone and estradiol. Early Hum Dev 2004;77:23-8. |
| 4. | Manning JT, Morris L, Caswell N. Endurance running and digit ratio (2D:4D): Implications for fetal testosterone effects on running speed and vascular health. Am J Hum Biol 2007;19:416-21. |
| 5. | Manning JT, Hill MR. Digit ratio (2D:4D) and Spring Speed in boys. Am J Hum Biol 2009;21:210-3. |
| 6. | Tester N, Campbell A. Porting achievement: What is the contribution of digit ratio? J Pers 2007;75:663-77. |
| 7. | Marek K, Raja C, Zofia I, Sławomir K. Is digit ratio (2D:4D) associated with the choice for the uniformed versus a civil study course by the Polish youth? Anthropol Rev 2019;82:177-90. |
| 8. | Agha-Alinejad H, Farzad B, Akbari M, Moffit DM, Dakhili A. Digit ratios and motor and health-related fitness in pre-adolescent females. Ann Hum Biol 2019;46:225-30. |
| 9. | Hull MJ, Schranz NK, Manning JT, Tomkinson GR. Relationships between digit ratio (2D:4D) and female competitive rowing performance. Am J Hum Biol 2015;27:157-63. |
| 10. | Hsu CC, Su B, Kan NW, Lai SL, Fong TH, Chi CP, et al. Elite collegiate tennis athletes have lower 2D:4D ratios than those of nonathlete controls. J Strength Cond Res 2015;29:822-5. |
| 11. | Sudhakar HH, Veena UB, Tejaswi RN. Digit ratio (2D:4D) and performance in Indian swimmers. Indian J Physiol Pharmacol 2013;57:72-6. |
| 12. | Abbott DH, Dumesic DA, Franks S. Developmental origin of polycystic ovary syndrome – A hypothesis. J Endocrinol 2002;174:1-5. |
| 13. | Ertuğrul B, Özener B, Pawłowski B. Prenatal exposure to oestrogens estimated by digit ratio (2d/4d) and breast size in young nulliparous women. Ann Hum Biol 2020;47:81-4. |
| 14. | Manning JT, Cook C, Crewther B. Digit ratio (2D:4D) and testosterone supplementations. Early Hum Dev 2019;139:104843. |
| 15. | Manning JT, Barley L, Walton J, Lewis-Jones DI, Trivers RL, Singh D, et al. The 2 nd: 4 th digit ratio, sexual dimorphism, population differences, and reproductive success. Evidence for sexually antagonistic genes? Evol Hum Behav 2000;21:163-83. |
| 16. | Shao XQ. Anthropometric Manual. Shang Hai, China: Shanghai, Shanghai Cishu Publishing House; 1985. |
| 17. | |
| 18. | |
| 19. | Kong DG, Gao H. Comparative study of body shape, body composition and bone density of urban and rural primary school students in Handan. Chin J School Health 2017;38:704-7. |
| 20. | Lu H, Wang L, Zhang C, Pei LG, Sheng YJ, Geng Z, et al. Relationships between digit ratio (2D:4D) and body mass index, waist-to-hip ratio in college students of Ningxia Han. Chin J Anat 2016;39:720-3. |
| 21. | Fink B, Neave N, Manning JT. Second to fourth digit ratio, body mass index, waist-to-hip ratio, and waist-to-chest ratio: Their relationships in heterosexual men and women. Ann Hum Biol 2003;30:728-38. |
| 22. | Muller DC, Manning JT, Hopper JL, English DR, Giles GG, Severi G. No strong association between second to fourth digit ratio (2D:4D) and adult anthropometric measures with emphasis on adiposity. Ann Hum Biol 2013;40:201-4. |
| 23. | Wang XZ, Luo HB, Leng ZW. Two-step cluster analysis of physical fitness of medical college students. Chin J Sch Health 2020;41:922-8. |
| 24. | Qu QY, Xiao YJ, Wen YF. Ren JZ, Xi HJ. Relationship between the digit ratio and physical fitness test of university students in Jinzhou. Chin J Anat 2019;42:64-7. |
| 25. | Wu YH, Zhang L, Wu YM, Wu YZ, Wang ZM, Wu JR, et al. Correlation between the digit ratio and physical fitness of Guangdong youths. Chin J Anat 2019;42:60-3. |
| 26. | Pasanen BE, Tomkinson JM, Dufner TJ, Park CW, Fitzgerald JS, Tomkinson GR. The relationship between digit ratio (2D:4D) and muscular fitness: A systematic review and meta-analysis. Am J Hum Biol 2022;34:e23657. |
| 27. | Lombardo MP, Otieno S. The associations between digit ratio, aerobic fitness, physical skills, and overall physical fitness of elite youth distance runners. Am J Hum Biol 2021;33:e23448. |
| 28. | Talarovicova A, Krskova L, Blazekova. Testosterone enhancement during pregnancy influ-ences the 2D:4D ratio and open field motor activity of rat siblings in adulthood. Horm Behav 2009;55:235-9. |
| 29. | Zheng Z, Cohn MJ. Developmental basis of sexually dimorphic digit ratios. Proc Natl Acad Sci U S A 2011;108:16289-94. |
| 30. | Auger J, Le Denmat D, Berges R, Doridot L, Salmon B, Canivenc-Lavier MC, et al. Environmental levels of oestrogenic and antiandrogenic compounds feminize digit ratios in male rats and their unexposed male progeny. Proc Biol Sci 2013;280:20131532. |
| 31. | Malas MA, Dogan S, Evcil EH, Desdicioglu K. Fetal development of the hand, digits and digit ratio (2D:4D). Early Hum Dev 2006;82:469-75. |
| 32. | Manning JT, Bundred PE, Taylor R. The Ratio of 2 nd and 4 th Digit Length: A Prenatal Correlate of Ability in Sport. Kinanthropometry VIII London: Roudledge; 2003. p. 165-74. |
| 33. | Golby J, Meggs J. Exploring the organizational effect of prenatal testosterone upon the sporting brain. J Sports Sci Med 2011;10:445-51. |
| 34. | Reed S, Meggs J. Examining the effect of prenatal testosterone and aggression on sportingchoice and sporting longevity. Pers Individ Diff 2017;116:11-5. |
| 35. | Hill R, Simpson B, Millet G, Manning J, Kilduff L. Right-left digit ratio (2D:4D) and maximal oxygen uptake. J Sports Sci 2012;30:129-34. |
| 36. | Paul SN, Kato BS, Hunkin JL, Vivekanandan S, Spector TD. The big finger: The second to fourth digit ratio is a predictor of sporting ability in women. Br J Sports Med 2006;40:981-3. |
| 37. | Trivers R, Hopp R, Manning J. A longitudinal study of digit ratio (2D:4D) and its relationships with adult running speed in Jamaicans. Hum Biol 2013;85:623-6. |
| 38. | Hönekopp J, T Manning J, Müller C. Digit ratio (2D:4D) and physical fitness in males and females: Evidence for effects of prenatal androgens on sexually selected traits. Horm Behav 2006;49:545-9. |
| 39. | Manning JT, Taylor RP. Second to fourth digit ratio and male ability in sport: Implications for sex-ual selection in humans. Evol Hum Behav 2001;22:61-9. |
| 40. | Deaner RO, Balish SM, Lombardo MP. Sex differences in sports interest and motivation: Anevolutionary perspective. Evol Behav Sci 2016;10:73-97. |
[Figure 1]
[Table 1], [Table 2], [Table 3], [Table 4]
|
Search Pubmed for