It is our hypothesis that physical .... of household support and equipment. (Table. I). The data resulting from the interviews .... Acta Orthop Scam! 1964; Suppl 65.
PHYSICAL
ACFIVITY
IN WOMEN
OF THE JAN
AsTR#{246}M,
SOLWEIG
NECK
AHNQVIST,
From
SUSTAINING
OF THE JACOMINA
Sundsvall
Hospital,
FRACTURE
FEMUR
BEERTEMA,
BRYNJOLFUR
JONSSON
Sweden
We have investigated the level of physical activity of 49 women between the ages of 15 and 45 years who a fracture of the neck of the femur at between 60 and 70 years of age, and compared this with the level of activity reported by 49 control subjects without fracture, who were matched for age and social status. We found that the patients had been significantly less physically active than the controls, especially as regards household duties and professional working conditions.
sustained
There has been a striking increase in the incidence of fractures of the neck of the femur during the past few decades in Scandinavia, particularly in urban areas. This is not entirely explained by the increased longevity of the population (Alffram 1964 ; Jensen 1980 ; Zetterberg, Andersson and Nachemson 1983 ; Johnell et al. 1984; Falch, Ilebekk and Slungaard 1985). The increase may reflect an increasing prevalence of osteoporosis (Rundgren et al. 1985). The reason for this is uncertain but physical inactivity due to urbanisation and a general rise in the standard of living may be significant (Chalmers and Ho 1970). Ethnic variation in population groups in one city have been shown to affect the local epidemiology ofhip fractures (Pogrund et al. 1977), while geographical and cultural factors also seem to influence the incidence (Chalmers and Ho 1970). It is our hypothesis that physical inactivity may increase the risk of sustaining an osteoporotic fracture. We therefore studied a group of women who had sustained a fracture of the neck of the femur at a relatively early age and matched them with a control group with the same age distribution. We then tried to evaluate and compare the physical activity of patients and control subjects during the fertile period of their lives.
J. S. J. B.
Astr#{246}m, MD, Orthopaedic Ahnqvist, Chief Occupational Beertema, MD, Orthopaedic J#{243}nsson, MD, Orthopaedic
Departments of Orthopaedics Hospital, S-85l 86 Sundsvall, Requests
for
reprints
© 1987 British 0301-620X/87/3l25
VOL.
69-B,
NO.
should
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3, MAY
Surgeon Therapist Surgeon Surgeon
and Occupational Sweden. be sent
Society
1987
to Dr
of Bone
Therapy,
J. Astr#{246}m.
and
Joint
Surgery
Sundsvall
PATIENTS
AND
METHODS
Using diagnostic registers, we located the medical records of all female patients who, at an age of between 60 and 70 years, had been admitted with a sub-capital or mid-cervical fracture of the neck of the femur to any of the four hospitals in the county of V#{228}sternorrland during a five-year period from January l980to December 1984. Trochanteric fractures were not included. We also excluded all patients with concomitant medical conditions known to induce or aggravate osteoporosis such as severe loss of locomotor function, rheumatoid arthritis, corticosteroid treatment, disease or injury of the central nervous system, psychiatric disorders requiring hospitalisation, stomach resection and other malabsorptioninducing conditions, alcoholism and diabetes mellitus requiring insulin. Patients who had left the district and those who had died before 1 May 1985 were also excluded. From the remaining total of 1 13 patients, 58 were found to have no obvious cause for osteoporosis. For each of these 58 patients, we selected four possible control subjects from the local population registry. In all cases these were women born within two days of the respective patient. Of these four possible controls, we chose the one who matched the patient most closely for type of residential area and civil status. These control subjects thus provided a representative age-matched group of the female population of the county. The population of V#{228}sternorrland is 264 000, of which 1 10 000 live in the city ofSundsvall and its surroundings. The county includes four smaller towns of which three have their own hospital. The age distribution pattern of the population differs from the rest of Sweden in having about 10% more individuals aged 65 years or more. The district is relatively highly industrialised, forestry being the main employment. Small scale farming used to be important, but this has mostly disappeared as a result of 381
J. ASTROM,
382
S. AHNQVIST,
agricultural rationalisation during the l940s and 1950s. Women have been exposed to heavy physical labour mainly in connection with farming and to a certain extent also with nursing. Interview procedure. Each of the 58 patients and the 58 controls was sent a written request to participate in a medical research project which would involve a telephone interview. A post-paid envelope was provided to facilitate refusal. If a patient did decline, both she and her control were excluded from the study. If a control subject declined, another of the four possible controls was chosen. All those who had not refused were telephoned by two ofthe authors who at the time were unaware whether the interviewee was a patient or a control subject. The interview was carried out from a questionnaire, which had been designed to survey physical activity between the ages of 15 and 45 years. Information was also collected on the presence of medical conditions which could induce osteoporosis. A scoring system was used to evaluate physical activity (Table I). Positive scores were awarded for raising children, for physically active professional work and for sporting activity. Negative scores were given for easy access to transport facilities, and for a high standard of household support and equipment (Table I). The data resulting from the interviews were registered in a Luxor ABC 850 computer, program IDA 800, and Student’s ttest was used for statistical analysis.
J. BEERTEMA, Table
B. JONSSON
I. Scoring
system
activity. Score
Positive
features
Raising
children
+ 5 per child
Activity at work Heavy, e.g.
+ 1 per year +05 per year
farming
Moderate, e.g. assistant Routine housework
nurse
0
Sport
Competitive
1 per year +05 per year
level
+
For exercise
Negative
features
Access
to transport Own car Use of family
-05
Household support and equipment Housemaid Access to washing machine
Passenger
I per year
-
car
-
lift in the house
-
per
I per
year
year
1 per year 1 per year
household (p = 0.024) showed the largest difference between the groups, while heavier working conditions alone produced a difference between the groups which approached the level of significance (p = 0.057). The patient group had also been less active in sport, but the difference was not significant (p = 0.180). There was little difference between the numbers of children raised by either group and both had had equal access to a car.
RESULTS Nine patients were excluded together with their controls. Four of them proved to have osteoporosis-inducing conditions which had not been noted in their medical records, two had moved from the district, two refused to participate and one patient had to be excluded since all of her four control subjects either refused to participate or had osteoporosis-inducing conditions. For each of the remaining 49 patients, one control subject was interviewed. Fifteen possible controls were excluded : 10 declined to participate, three had conditions likely to cause osteoporosis and two had changed their home address. Each of these 15 was replaced by another age-matched control. The replacement of firstchoice controls slightly reduced the precise matching of the two groups. As a result, for patients and controls respectively the residential areas were : city 16 and 15, small town 14 and 12 and countryside 19 and 22. As regards civil status the respective distributions were: married 28 and 26, single 3 and 1, divorced 4 and 5 and widowed 14 and 17. The mean total score for the 49 patients was +10.01 points and for the control group + 16.89 points, a significant difference (p = 0.012). The separate scores for the five estimates of activity are given in Table II with their p-values. The technical and social standard of the
for physical
DISCUSSION Several authors have found that the long-term mechanical loading of bones by exercise may prevent postmenopausal osteoporosis (Aloia Ct al. 1978 ; Kr#{248}lneret al. 1983 ; White et al. 1984). In our investigation we took no account of physical activity near the time of fracture, our hypothesis being that relative inactivity during the fertile period of life increases the risk of sustaining a hip fracture during early ageing. We therefore tried to evaluate the activity of patients and control subjects Table II. Mean scores for estimated physical period in 49 patients and 49 controls
activity
during
the fertile
Significance Physical Total
activity
Patients
Controls
l00l
l689
00l2
933
980
0356
711
1013
0057
110
l83
0l80
-
228
0322
-
259
0024
score
Separate
scores
Raising
children
Conditions Sporting
Transport Standard
of difference
for:
at work activity
facilities
-
of household
261
-492
THE
JOURNAL
OF BONE
AND
JOINT
SURGERY
(p)
PHYSICAL
ACTIVITY
IN WOMEN
SUSTAINING
between the ages of 15 and 45. At the age of 45 few people experience any drastic changes in their professional or spare-time occupations. Thus a woman who has been very active up to the age of 45 will probably continue to be so after that age, and this also may help to prevent the development of postmenopausal osteoporosis. It is also possible that very active women have built up a more dense bone mass by the onset of the menopause, which means that postmenopausal loss would take much longer to reduce the mass to a level compatible with an osteoporotic fracture. In designing our investigation we used access to a washing machine as one parameter for the technical standard of the household. However, in the course of the interviews we came to realise that during the period of the survey of physical activity (1925-1969) many households lacked running water, main sewerage and central heating. Many women had to carry the daily requirements of water and firewood. This source of physical exertion was unfortunately left out of consideration in our study ; its possible effects on the results are not known. Our results indicate that patients sustaining hip fractures at a relatively early age had been less active physically during their fertile period than matched control subjects.
VOL.
69-B,
NO.
3, MAY
1987
FRACTURE
OF THE
NECK
OF THE
383
FEMUR
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