11.2 Obesity, Osteoporosis, Bone Health & Social Prescribing

Obesity, Osteoporosis, Bone Health & Social Prescribing

Three of RCSI's topic headings sit together here because they share a frame: each is a long-term health issue where the nurse's main intervention is assessment, measurement and a well-conducted conversation rather than an acute procedure. RCSI names obesity, BMI and waist circumference and osteoporosis, osteopenia and DEXA scan as teaching the junior student nurse examples, and lists social prescribing as a topic in its own right.

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Obesity: Measurement

Body Mass Index

BMI = weight in kilograms divided by height in metres squared.

What BMI cannot tell you. It does not distinguish muscle from fat, so a heavily muscled person may be classified as overweight without excess adiposity. It says nothing about where fat is distributed. It performs differently across ethnic groups, with cardiometabolic risk rising at lower BMI values in South Asian populations. And it is uninterpretable in pregnancy, in significant oedema or ascites, and in people who cannot stand for an accurate height.

Waist Circumference

Waist circumference measures central (visceral) adiposity, which is the fat depot most strongly associated with type 2 diabetes, cardiovascular disease and metabolic syndrome. This is why RCSI pairs it with BMI.

Technique determines whether the number means anything:

1. Measure against bare skin, not over clothing.
2. Locate the midpoint between the lowest rib margin and the top of the iliac crest.
3. Wrap the tape horizontally, snug but not compressing the skin.
4. Ask the person to breathe out normally and measure at the end of that expiration.
5. Record to the nearest centimetre, and repeat for consistency.

Thresholds are lower for some ethnic groups, so check the guidance applicable to the person in front of you.

Talking About Weight

The conversation is the intervention, and it is easy to do badly.

• Ask permission before raising weight: "Would it be all right if we talked about your weight today?"
• Use neutral language. "Weight" and "BMI" are acceptable to most people; "fat" and "obese" used as descriptions of the person are not. Say a person with obesity, not an obese person.
• Treat obesity as a chronic, relapsing condition with genetic, metabolic, psychological, social and environmental determinants - not as a failure of willpower. Ask about medications that cause weight gain, mobility limitation, chronic pain, mood, sleep, shift work, food cost and food access.
• Set realistic goals. A 5 to 10% weight loss produces clinically meaningful improvements in blood pressure, glycaemic control and lipids, well before any change in dress size.
• Use the food pyramid and the national physical activity guidance as your teaching tools, and signpost the HSE weight management pathway, dietetics, the chronic disease management programme and community supports.
• Check the environment too. Appropriate chairs, a hoist with adequate safe working load, a correctly sized blood pressure cuff and a gown that fits are part of dignified care - and the wrong BP cuff produces a falsely high reading.

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Osteoporosis and Bone Health

The Pathophysiology in One Paragraph

Bone is continuously remodelled: osteoclasts resorb bone and osteoblasts lay down new matrix. Peak bone mass is reached in early adulthood; thereafter resorption gradually outpaces formation. In osteoporosis, bone mineral density falls and the trabecular microarchitecture deteriorates, so bone becomes porous and fragile. It is asymptomatic until it fractures - which is exactly why screening and prevention matter.

Risk Factors

Diagnosis: DEXA and the T-Score

Dual-energy X-ray absorptiometry (DEXA or DXA) measures bone mineral density, usually at the hip and lumbar spine. It is quick, painless and uses a very low radiation dose - lower than a chest X-ray - which is the reassurance patients most often need.

The result is reported as a T-score: the number of standard deviations the person's bone density lies from that of a healthy young adult.

A Z-score compares the person with others of the same age and sex, and is used in younger adults and children.

Patient preparation: no special preparation beyond avoiding calcium supplements on the day and avoiding recent contrast or nuclear medicine studies; metal fastenings, zips and jewellery should be removed. The person lies still on a table for a few minutes and remains fully clothed in suitable garments.

Fragility Fractures

A fragility fracture results from force that would not normally break a bone - typically a fall from standing height or less. The classic sites are the hip, vertebrae and distal radius (Colles' fracture). Vertebral fractures often occur without a fall at all and may present as sudden back pain, progressive height loss or a developing kyphosis.

Prevention and Nursing Management

• Calcium and vitamin D: adequate dietary calcium from dairy, fortified foods, tinned fish with bones and green vegetables, with supplementation as prescribed. Vitamin D matters especially in Ireland, where limited sunlight, older age, housebound status, darker skin and covered clothing all reduce synthesis.
• Weight-bearing and resistance exercise maintains bone and, just as importantly, maintains the muscle strength and balance that prevent falls.
• Smoking cessation and alcohol within low-risk limits.
• Falls prevention is inseparable from fracture prevention: medication review, vision check, footwear, home hazards, continence, and strength and balance training.
• Medicines: bisphosphonates are commonly first line, and the administration instructions are a nursing responsibility. An oral bisphosphonate is taken on an empty stomach first thing in the morning with a full glass of plain water, and the patient must remain upright and take nothing else by mouth for at least 30 minutes to prevent oesophageal irritation and ulceration. Other options include denosumab and, in selected cases, teriparatide.
• Signpost the Irish Osteoporosis Society for patient information and support.

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Social Prescribing

Social prescribing connects people with non-clinical, community-based supports to improve health and wellbeing. A link worker (sometimes called a community connector) meets the person, explores what matters to them, and connects them to local activities and services.

What people are linked to: walking groups and exercise classes, art, music and men's sheds, gardening and community allotments, volunteering, adult education, befriending schemes, bereavement support, and practical advice on benefits, housing and debt.

Who benefits: people experiencing loneliness or social isolation, mild to moderate anxiety or low mood, inactivity, long-term conditions with a significant self-management component, carers, and people who attend healthcare frequently for problems whose roots are social rather than medical.

Why it belongs in a nursing curriculum. It is the practical expression of treating the whole person: recognising that a housebound older man's deconditioning and low mood may respond more to a weekly group than to another prescription. In Ireland social prescribing is coordinated through the All-Ireland Social Prescribing Network and is delivered in partnership with primary care, community healthcare services and the voluntary sector.

Referral is usually simple: discuss it with the person, obtain their agreement, and refer to the local link worker. As with any referral, record the discussion, the consent and the referral in the healthcare record.