The Special Study, Tromsø IV

The Special Study featured a significant increased co-operation with the clinical departments at the Regional Hospital in Tromsø (now the University Hospital of Northern Norway, UNN).

Everyone in the 55-74 age group, 5-10 percent in the 25-54 and 75-85 age groups, and all men under the age of 55 who had participated in the Family Intervention Study, were given the opportunity to participate in this study. In addition, a random selection of women in the 25-35 age group and all women in the 50-54 age group were given the opportunity to have their bone mineral density measured. Unfortunately, these women were not subject for all the other examinations like e.g., ultrasound examination.

Attendance to the Special Study, 1994-95

Age	Invited men	Invited women	Attended men	Attended women	% men	% women
25-29	134	190	56	93	41,8	49,0
30-34	96	201	49	124	51,0	61,7
35-39	125	145	75	94	60,0	64,8
40-44	100	109	62	85	62,0	78,0
45-49	296	116	230	100	77,7	86,2
50-54	290	1434	228	1072	78,6	74,8
55-59	1068	1015	809	863	75,8	85,0
60-64	900	850	714	713	79,3	83,9
65-69	807	965	624	779	77,3	80,7
70-74	732	821	516	599	70,5	73,0
75-79	44	53	29	31	65,9	58,5
80-84	14	37	5	15	35,7	40,5
TOTALT	4606	5936	3397	4568	73,8	77,0

The table above also included 1485 women who were only invited to undergo a bone mineral density examination. A total of 76 percent of the population of Tromsø in our target group accepted our invitation to participate (see above). If you do not take into account people who had moved or died before the study, the participation rate was 78 percent.

The study contents
A separate information brochure was prepared for the Special Study. The Special Study comprised of measuring the waist and hip circumference, an ultrasound examination of the carotid artery, main artery (aorta) and an echocardiography of the heart, a 12-part EKG, measurement of bone mineral density and a host of new blood tests (such as insulin and pro-insulin, glycosylated haemoglobin, fructosamine, calcium, PTH and fibrinogen) and a urine test (3 days urine sample to analyse, among other things, protein and creatinin). All medications used by the participants were recorded.

What did we discover?
The Special Study was the basis for a host of Ph.Ds. Themes included fractures and brittleness of the bones (osteoporosis), echocardiography and hardening of the arteries (atherosclerosis) in the carotid artery (both the thickness of the artery wall and major visual changes (plaque)). The results confirm that atherosclerosis in the carotid artery significantly increase the risk of death, but also indicate that not all types of plaques are equally as dangerous. A prolonged raised blood sugar level (measured by a raised glycosylated haemoglobin, HbA1c) among people not suffering from diabetes is only connected with the least dangerous known type of plaque. Methodological work was also conducted, including within the research concerning osteoporosis.