ORIGINAL STUDY
Changes in Intraocular Pressure and Associated Systemic Factors Over 10 Years in Subjects Without Ocular Disease at Baseline Kazuyoshi Kitamura, MD,* Hiroshi Yokomichi, MD,w Zentaro Yamagata, MD, PhD,w Masahiro Tsuji, MA,z Yoshiki Yoda, MD,z and Kenji Kashiwagi, MD, PhD*
Purpose: To investigate the changes in intraocular pressure (IOP) and associated factors over 10 years in subjects who participated in health examinations in 1999 and 2008. Subjects and Methods: Subjects with no clear history of ocular disease and who participated in health examinations at Yamanashi Koseiren Health Care Center, Japan, in 1999 and 2008 were enrolled in this study. IOP was evaluated using a noncontact tonometer. The right eye was analyzed in all subjects. The change in IOP between the 2 examinations and the factors that were significantly associated with the change in IOP were investigated. Results: A total of 3785 subjects were enrolled (mean age, 50.9 ± 8.6 y), comprising 2022 males (mean age, 50.3 ± 8.9 y) and 1763 females (mean age, 51.5 ± 8.2 y). The mean IOPs of males and females in 1999 were 13.4 ± 3.1 and 12.8 ± 2.8 mm Hg, respectively (P < 0.0001). IOP measured in 2008 was significantly lower than that in 1998 in males and females (mean change, 0.8 and 0.6 mm Hg, respectively; P < 0.0001). Univariate regression analysis showed that changes in systolic blood pressure, diastolic blood pressure, total cholesterol, body mass index, and g-glutamyl transpeptidase were positively correlated with change in IOP. Multivariate regression analysis showed that the change in IOP was positively associated with the changes in systolic blood pressure, diastolic blood pressure, and body mass index. Conclusions: IOP decreased significantly with age. Several systemic factors were significantly correlation with the change in IOP. Key Words: intraocular pressure, body mass index, blood pressure, metabolic syndrome
(J Glaucoma 2014;23:185–189)
I
ntraocular pressure (IOP) is a major risk factor for the onset and progression of glaucoma. Many previous studies have reported a relationship between the change in IOP and age, sex, obesity, and other factors.1–8 IOP was reported to increase with age in black and white people,2–5,8–10 whereas it decreases with age in Japanese people.11–13 Previous reports have shown a positive correlation between obesity and the age-related change in
Received for publication December 20, 2011; accepted September 11, 2012. From the Departments of *Ophthalmology; wHealth Sciences, Faculty of Medicine, University of Yamanashi, Chuo; and zYamanashi Koseiren Health Care Center, Kofu, Japan. Disclosure: The authors declare no conflict of interest. Reprints: Kenji Kashiwagi, MD, PhD, Department of Ophthalmology, University of Yamanashi, Chuo, Japan 409-3898 (e-mail: kenjik@ yamanashi.ac.jp). Copyright r 2012 by Lippincott Williams & Wilkins DOI: 10.1097/IJG.0b013e3182741c51
J Glaucoma
Volume 23, Number 3, March 2014
IOP.5,11,14–17 However, many of these studies were crosssectional in design. In one of the first longitudinal studies to examine this issue, McLeod et al18 reported a positive correlation between IOP and systolic blood pressure (SBP). Meanwhile, Hennis and colleagues conducted a 4-year longitudinal study of a population that included white and black people, and showed that IOP increased significantly with age. They also reported that the increase in IOP was accelerated by high levels of hemoglobin A1c (HbA1c), low baseline IOP, and concomitant hypertension and diabetes mellitus.9 Wu et al19 reported that IOP increased among persons aged between 50 and 59 years but tended to decrease among persons aged Z70 years in their 9-year longitudinal study. Mori et al20 performed cross-sectional and longitudinal studies to investigate the association between IOP and obesity. Their cross-sectional study showed that IOP was significantly higher in males than in females, and that IOP was positively correlated with body mass index (BMI). Meanwhile, their longitudinal study showed that the change in IOP was positively correlated with the change in body weight.20 Despite these findings, the effects of age and other factors on the change in IOP remain poorly understood. The results of our previously reported 10-year longitudinal study showed that IOP decreased with age in Japanese subjects13; however, the number of subjects in this study was small. Therefore, the present study investigated the changes in IOP and its associated factors in a larger scale 10-year longitudinal study.
SUBJECTS AND METHODS This study was approved by the University of Yamanashi Ethics Committee and was performed in accordance with the Declaration of Helsinki. Informed consent was obtained from all participants.
Subjects Subjects who participated in health examinations at Yamanashi Koseiren Health Care Center, Japan, in 1999 and 2008 were enrolled. IOP was evaluated using a noncontact tonometer (NT-3000; Nidek, Gamagori, Japan) in examinations performed between 9 and 12 AM. The right eye was analyzed in all subjects. If the IOP was Z22 mm Hg or if IOP differed by Z4 mm Hg between the right and left eyes, IOP was remeasured. If the values did not change, even after repeating the measurements 3 times, the final value was used in the analysis. Subjects with the following conditions were excluded: history of ocular disease, any fundus disease observed at the www.glaucomajournal.com |
185
Kitamura et al
J Glaucoma
Volume 23, Number 3, March 2014
fundus examination in 1999, subjects who required a secondary examination or treatment, IOP Z25 or
Changes in Intraocular Pressure and Associated Systemic Factors Over 10 Years in Subjects Without Ocular Disease at Baseline Kazuyoshi Kitamura, MD,* Hiroshi Yokomichi, MD,w Zentaro Yamagata, MD, PhD,w Masahiro Tsuji, MA,z Yoshiki Yoda, MD,z and Kenji Kashiwagi, MD, PhD*
Purpose: To investigate the changes in intraocular pressure (IOP) and associated factors over 10 years in subjects who participated in health examinations in 1999 and 2008. Subjects and Methods: Subjects with no clear history of ocular disease and who participated in health examinations at Yamanashi Koseiren Health Care Center, Japan, in 1999 and 2008 were enrolled in this study. IOP was evaluated using a noncontact tonometer. The right eye was analyzed in all subjects. The change in IOP between the 2 examinations and the factors that were significantly associated with the change in IOP were investigated. Results: A total of 3785 subjects were enrolled (mean age, 50.9 ± 8.6 y), comprising 2022 males (mean age, 50.3 ± 8.9 y) and 1763 females (mean age, 51.5 ± 8.2 y). The mean IOPs of males and females in 1999 were 13.4 ± 3.1 and 12.8 ± 2.8 mm Hg, respectively (P < 0.0001). IOP measured in 2008 was significantly lower than that in 1998 in males and females (mean change, 0.8 and 0.6 mm Hg, respectively; P < 0.0001). Univariate regression analysis showed that changes in systolic blood pressure, diastolic blood pressure, total cholesterol, body mass index, and g-glutamyl transpeptidase were positively correlated with change in IOP. Multivariate regression analysis showed that the change in IOP was positively associated with the changes in systolic blood pressure, diastolic blood pressure, and body mass index. Conclusions: IOP decreased significantly with age. Several systemic factors were significantly correlation with the change in IOP. Key Words: intraocular pressure, body mass index, blood pressure, metabolic syndrome
(J Glaucoma 2014;23:185–189)
I
ntraocular pressure (IOP) is a major risk factor for the onset and progression of glaucoma. Many previous studies have reported a relationship between the change in IOP and age, sex, obesity, and other factors.1–8 IOP was reported to increase with age in black and white people,2–5,8–10 whereas it decreases with age in Japanese people.11–13 Previous reports have shown a positive correlation between obesity and the age-related change in
Received for publication December 20, 2011; accepted September 11, 2012. From the Departments of *Ophthalmology; wHealth Sciences, Faculty of Medicine, University of Yamanashi, Chuo; and zYamanashi Koseiren Health Care Center, Kofu, Japan. Disclosure: The authors declare no conflict of interest. Reprints: Kenji Kashiwagi, MD, PhD, Department of Ophthalmology, University of Yamanashi, Chuo, Japan 409-3898 (e-mail: kenjik@ yamanashi.ac.jp). Copyright r 2012 by Lippincott Williams & Wilkins DOI: 10.1097/IJG.0b013e3182741c51
J Glaucoma
Volume 23, Number 3, March 2014
IOP.5,11,14–17 However, many of these studies were crosssectional in design. In one of the first longitudinal studies to examine this issue, McLeod et al18 reported a positive correlation between IOP and systolic blood pressure (SBP). Meanwhile, Hennis and colleagues conducted a 4-year longitudinal study of a population that included white and black people, and showed that IOP increased significantly with age. They also reported that the increase in IOP was accelerated by high levels of hemoglobin A1c (HbA1c), low baseline IOP, and concomitant hypertension and diabetes mellitus.9 Wu et al19 reported that IOP increased among persons aged between 50 and 59 years but tended to decrease among persons aged Z70 years in their 9-year longitudinal study. Mori et al20 performed cross-sectional and longitudinal studies to investigate the association between IOP and obesity. Their cross-sectional study showed that IOP was significantly higher in males than in females, and that IOP was positively correlated with body mass index (BMI). Meanwhile, their longitudinal study showed that the change in IOP was positively correlated with the change in body weight.20 Despite these findings, the effects of age and other factors on the change in IOP remain poorly understood. The results of our previously reported 10-year longitudinal study showed that IOP decreased with age in Japanese subjects13; however, the number of subjects in this study was small. Therefore, the present study investigated the changes in IOP and its associated factors in a larger scale 10-year longitudinal study.
SUBJECTS AND METHODS This study was approved by the University of Yamanashi Ethics Committee and was performed in accordance with the Declaration of Helsinki. Informed consent was obtained from all participants.
Subjects Subjects who participated in health examinations at Yamanashi Koseiren Health Care Center, Japan, in 1999 and 2008 were enrolled. IOP was evaluated using a noncontact tonometer (NT-3000; Nidek, Gamagori, Japan) in examinations performed between 9 and 12 AM. The right eye was analyzed in all subjects. If the IOP was Z22 mm Hg or if IOP differed by Z4 mm Hg between the right and left eyes, IOP was remeasured. If the values did not change, even after repeating the measurements 3 times, the final value was used in the analysis. Subjects with the following conditions were excluded: history of ocular disease, any fundus disease observed at the www.glaucomajournal.com |
185
Kitamura et al
J Glaucoma
Volume 23, Number 3, March 2014
fundus examination in 1999, subjects who required a secondary examination or treatment, IOP Z25 or
