1. ¹Department of Preventive Medicine and Health Promotion Research Center, School of Medicine, Kyungpook University, Daegu, Korea
2. ²Health Care Center, Pohang Steel Company, Pohang, Korea
3. ³Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, MN, USA
4. ⁴Institute for Nutrition Research, University of Oslo, Oslo, Norway

Correspondence: Dr D-H Lee, Department of Preventive Medicine, School of Medicine, Kyungpook University 101 Dongin-dong, Jung-gu, Daegu 700422, Korea. E-mail: lee_dh@knu.ac.kr

Received 8 September 2003; Revised 23 February 2004; Accepted 27 February 2004; Published online 13 May 2004.

Abstract

We performed a prospective study to assess whether the relationship of age with hypertension was stronger in men with high normal serum gamma glutamyltransferase (GGT) than in those with lower GGT levels. The study population included 8170 healthy male workers in a steel manufacturing company who had undergone health examinations in both 1994 and 1998. The higher the baseline GGT level, the effect of age on the development of hypertension was stronger. The incidence of hypertension among those aged 25–34, 35–44 and 45–50 years was 0.9, 2.2, 3.8% in those with GGT<20 U/l; 1.0, 4.1, 12.5% in those with GGT between 20 and 39 U/l; and 1.9, 6.3, 17.2% in those with GGT40 U/l, respectively. All relationships persisted after adjusting for baseline values of body mass index, alcohol intake, smoking, exercise, family history of hypertension, systolic and diastolic blood pressure, and changes of body mass index during 4 years (P for interaction=0.03). Our data supported the hypothesis that the effect of age on the development of hypertension differed by baseline GGT level, although the underlying mechanism for this interaction is unclear.